The question in this case is the propriety of filing a Supplemental Complaint in order to seek a different relief in view of developments rendering the original relief impossible of attainment.

The facts are as follows:

On November 8, 1989, petitioner Superclean Services filed with the Regional Trial Court of Manila a complaint for Mandamus/Certiorari With Preliminary Injunction And/Or Restraining Order against private respondent Home Development and Mutual Fund. Petitioner alleged that at the public bidding for janitorial services for the year 1990 it was the "lowest or best bidder," but private respondent refused without just cause to award the contract to it and instead caused the publication on October 23, 1989 of a Notice of Rebidding to be held on November 9, 1989.

In its answer private respondent defended its action on the ground that not a single bid submitted complied with the terms and conditions agreed upon in the pre-bidding conference held on September 6, 1989.

The trial court thereafter set petitioner's application for preliminary injunction for hearing and in the meantime ordered private respondent to desist from conducting a rebidding. At the same time, the court granted leave to private respondent on January 4, 1990 to hire janitorial services on a month-to-month basis to insure the maintenance of its offices.

On July 24, 1991, petitioner moved for the admission of a "Supplemental Complaint."^[1] Petitioner alleged that because the contract of services was for the furnishing of janitorial service for the previous year 1990, the delay in the decision of the case had rendered the case moot and academic "without [petitioner] obtaining complete relief to redress the wrong committed against it by [private respondent], which relief consists in unrealized profits, exemplary damages and attorney's fees." Accordingly, instead of pursuing its prayer for a writ of mandamus, petitioner sought the payment of damages to it.

On August 23, 1991, the trial court denied petitioner's motion, finding "no merit in and no basis supporting it" and set the continuation of the trial on September 19, 1991.

Petitioner filed a motion for reconsideration, but its motion was likewise denied. In its order dated November 25, 1991, the trial court said that admission of the "Supplemental Complaint" would "not only radically but substantially [change] the issues" by "materially var[ying] the grounds of relief, and would operate unjustly to the prejudice of the rights of [private respondent]."

Petitioner filed a petition for certiorari in the Court of Appeals which, on August 5, 1992, rendered a decision, finding no grave abuse of discretion to have been committed by the trial court in not admitting petitioner's "Supplemental Complaint" and denying the motion for reconsideration of its order. Its ruling was based on the fact that the relief sought in the "Supplemental Complaint" was different from that contained in the original complaint which sought to compel private respondent to recognize petitioner as the lowest qualifying bidder. In addition, the appellate court held that the original complaint had been rendered moot and academic by supervening events and that a supplemental complaint was inappropriate since "supplemental pleadings are meant to supply the deficiency in aid of the original pleading, not to entirely substitute the latter."

Petitioner moved for a reconsideration, but its motion was denied in a resolution of the Court of Appeals dated October 30, 1992. Hence, this petition for review on certiorari.

First. The "Supplemental Complaint" appears to have been filed under Rule 10 of the Rules of Court which provides:

§6. Matters Subject of Supplemental Pleadings. " Upon motion of a party the court may, upon reasonable notice and upon such terms as are just, permit him to serve a supplemental pleading setting forth transactions, occurrence or events which have happened since the date of the pleading sought to be supplemented. If the court deems it advisable that the adverse party should plead thereto, it shall so order, specifying the time therefor.

The transaction, occurrence or event happening since the filing of the pleading, which is sought to be supplemented, must be pleaded in aid of a party's right or defense as the case may be.^[2] But in the case at bar, the supervening event is not invoked for that purpose but to justify the new relief sought.

To begin with, what was alleged as a supervening event causing damage to petitioner was the fact that the year for which the contract should have been made had passed without the resolution of the case. Only incidentally was it claimed that because of the award of a contract for janitorial services, on a month-to-month basis to a third party, petitioner failed to realize profits. In its "Supplemental Complaint" petitioner alleged:

1.  Supervening events not attributable to anybody which consist in the delay in the early disposition of the case within the one (1) year period life span of the contract for janitorial services, have rendered the case moot and academic, without plaintiff obtaining complete relief to redress the wrong committed against it by defendant, which is the unjustified and/or unlawful refusal of defendant to recognize plaintiff as the lowest qualifying bidder for janitorial services for the year 1990;

2.  By reason of the unjustified refusal of defendant to recognize the result of the public bidding held in September 1989 and to award to plaintiff the contract for janitorial services as the lowest qualifying bidder favorable and advantageous to the defendant for the year 1990, and by hiring another entity to perform janitorial services during the pendency of the suit, plaintiff suffered unrealized profits in the sum of P158,117.28;

The supervening event was therefore cited not to reinforce or aid the original demand, which was for the execution of a contract in petitioner's favor, but to say that, precisely because of it, petitioner's demand could no longer be enforced, thus justifying petitioner in changing the relief sought to one for recovery of damages. This being the case, petitioner's remedy was not to supplement, but rather to amend its complaint.

Indeed the new relief sought (payment of damages in lieu of an award of the contract for janitorial services) is actually an alternative remedy to which petitioner was entitled even before at the time of the filing of its original complaint. If petitioner was entitled to the award of the contract, as it claimed it was, it could have asked either for an award of the contract for janitorial services or for damages. The fact that it opted for the first does not preclude it from subsequently claiming damages because through no fault of its own, the year passed without an award in its favor, with the result that it could no longer demand the execution of a contract in its favor after that year.

Be that as it may, the so-called Supplemental Complaint filed by petitioner should simply be treated as embodying amendments to the original complaint or petitioner may be required to file an amended complaint.

Second. But, it is contended, such an amendment of the complaint would change the theory of the case. Three reasons were cited by the Court of Appeals why it thought the trial court correctly refused to admit the so-called Supplemental Complaint of petitioner: (1) change in the reliefs prayed for; (2) change in the issues of the case; and (3) prejudice to the rights of private respondent.

The contention has no merit. An amendment to change the relief sought does not change the theory of a case. What is prohibited is a change in the cause of action. Thus in Arches v. Villarruz,^[3] it was held:

The lower court denied the admission of the amended complaint on the ground that the plaintiff therein has changed the action alleged in the original complaint, but upon comparing the two complaints, we find that, essentially, there was no change of action for, in both the original and the amended complaints, the action was for the collection of the value of the same promissory notes and the only difference between the original and the amended complaints is with regard to the consideration of said promissory notes, for while in the original complaint it was alleged that these were executed by defendant Villarruz for money obtained from plaintiff Arches and with which the former paid for labor and materials for the construction and completion of the Ivisan Bridge, in the amended complaint it was alleged that said promissory notes were executed for materials supplied to William Villarruz and actually used in the construction of the Ivisan Bridge. While the rule allowing amendments to a pleading is subject to the general limitation that the cause of action should not be substantially changed or that the theory of the case should not be altered, in the furtherance of justice, amendments to a pleading should be favored and the rules thereon should be liberally construed. In the present case, we find justification for allowing the admission of the amended complaint in order that the real question between the parties may be properly and justly threshed out, in a single proceeding, and thus avoid multiplicity of actions.

In Vda. de Villaruel v. Manila Motor Co., Inc.,^[4] plaintiffs, as lessors of a property, filed an action for the rescission of the contract of lease for alleged refusal of defendants to pay rentals. While the case was pending, the buildings leased were destroyed by fire. Plaintiffs filed a supplemental complaint for the recovery of the value of the burned buildings. In holding the supplemental complaint proper, this Court held:

This action was inceptionally instituted for the rescission of the contract of lease and for the recovery of unpaid rentals before and after liberation. When the leased buildings were destroyed, the plaintiffs-lessors demanded from the defendants-lessees, instead, the value of the burned premises, basing their right to do so on defendants' alleged default in the payment of post-liberation rentals (which was also their basis in formerly seeking for rescission). This cannot be considered as already altering the theory of the case which is merely a change in the relief prayed for, brought about by circumstances occurring during the pendency of the action, and is not improper. (Southern Pacific Co. vs. Conway, 115 F. 2d 746; Suburban Improvement Company vs. Scott Lumber Co., 87 A.L.R. 555, 59 F. 2d 711). The filing of the supplemental complaint can well be justified also under Section 2, Rule 17 of the Rules of Court (on amendments) "to the end that the real matter in dispute and all matters in the action in dispute between the parties may, as far as possible be completely determined in a single proceeding." It is to be noted furthermore, that the admission or rejection of this kind of pleadings is within the sound discretion of the court that will not be disturbed on appeal in the absence of abuse thereof (see Sec. 5, Rule 17, Rules of Court), especially so, as in this case, where no substantial procedural prejudice is caused to the adverse party.^[5]

In this case, the original complaint for Mandamus/Certiorari With Preliminary Injunction And/Or Restraining Order alleged, as cause of action, private respondent's unjustifiable refusal to award the contract to petitioner despite the fact that the latter was the "lowest and best qualifying bidder." On the basis of this allegation, it was prayed that:

1.  Upon filing [of] this Complaint, a restraining order be issued to enjoin [private respondent] from implementing [or] proceeding with its Notice of Rebidding which is scheduled on November 9, 1989 at 10:00 A.M.;

2.  After trial on the merits, judgment be rendered-

a. ordering [private respondent] to recognize [petitioner] as the lowest qualifying responsive bidder at the public bidding held on September 22, 1989 and therefore its right to the award of the contract for janitorial services;

b. declaring that [private respondent] in publishing its "Notice of Rebidding" acted with grave abuse of discretion amounting to excess and/or lack of jurisdiction;

c. declaring the restraining order or temporary writ of injunction to be permanent; and

d. for costs of suit.

These same allegations constitute petitioner's cause of action for damages, to wit:

1. the sum of P158,117.28 as unrealized profits;

2. the sum of P50,000.00 as exemplary damages;

3. the sum equivalent to twenty-five (25%) percent of the total amount due and demandable, plus P1,000.00 for every appearance of counsel in court;

4. the costs of suit.

As already stated, the change in the relief sought was necessitated by a supervening event which rendered the first relief sought impossible of attainment.

Because the cause of action on which the complaint for mandamus and injunction and the so-called Supplemental Complaint are based is one and the same, the issue raised is the same, namely, whether private respondent was justified in refusing to award the contract for janitorial services to petitioner.

Nor would admission of the amended complaint prejudice the rights of private respondent as defendant in the action below, as the Court of Appeals held. Indeed neither the trial court nor the appellate court showed in what way the rights of private respondent would be prejudiced by the allowance of the amendment in question. There will be no unfairness or surprise to private respondent, because after all private respondent will have a right to file an amended answer and present evidence in support thereof.^[6]

Third. The Court of Appeals also held that the action for mandamus and/or injunction had become moot and academic and consequently there was no longer any complaint to be supplemented. It is true that a supplemental or an amended pleading presupposes the existence of a pleading. What was rendered moot and academic, however, was not petitioner's cause of action but only its prayer for the writ of mandamus. There was still an alternative remedy left to petitioner of seeking damages in lieu of an award of the contract. The situation is similar to an action for illegal dismissal in labor law. If reinstatement is no longer possible, because the position has been abolished and there is no way the dismissed employee can be reinstated to a comparable position, the employee's action is not thereby rendered moot and academic. He can instead ask for separation pay.

Indeed, what is important is that, as already stated, the basic allegations of fact in the original and in the amended complaints are the same, namely, that private respondent, without justification, refused to award the contract of services to petitioner. Through no fault of petitioner, the year for which janitorial services were to be rendered expired without the resolution of petitioner's case. It would be to exalt technicality over substance to require that petitioner file a new complaint. It would best serve the interests of justice if the so-called Supplemental Complaint is simply considered as embodying amendments to the original complaint. In fact it appears that the court ordered a continuation of the trial on September 19, 1991, despite petitioner's statement in its Supplemental Complaint that the original case had become moot and academic.

WHEREFORE, the decision of the Court of Appeals is REVERSED and the case is REMANDED to the trial court with instructions to admit the "Supplemental Complaint" and to treat it as an amendment to the original complaint or to require petitioner to file an amended complaint, merging the relevant allegations of its original complaint and "Supplemental Complaint," and thereafter to allow private respondent to file an answer.

SO ORDERED.

Regalado, (Chairman), Romero, and Puno, JJ., concur.
Torres, Jr., J., took no part.

---

^[1] Rollo, p. 48.

^[2] De la Rama Steamship Co., Inc. v. National Development Co., 6 SCRA 775 (1962).

^[3] 102 Phil. 661, 668 (1957).

^[4] 104 Phil. 926 (1958).

^[5] Id., at 932-933.

^[6] Rule 11, §3.