Rule 15 - Amended and Supplemental Pleadings(a) Amendments before trial.(a)(1) A party may amend its its pleading once as a matter of course within:(a)(1)(A) 21 days after serving it; or (a)(1)(B) if the pleading is one to which a responsive pleading is required, 21 days after service of a responsive pleading or 21 days after service of a motion under Rule 12(b), (e), or (f), whichever is earlier. (a)(2) In all other cases, a party may amend its pleading only with the court's permission or the opposing party's written consent. The party must attach its proposed amended pleading to the motion to permit an amended pleading. The court should freely give permission when justice requires.(a)(3) Any required response to an amended pleading must be filed within the time remaining to respond to the original pleading or within 14 days after service of the amended pleading, whichever is later.(b) Amendments during and after trial.(b)(1) When an issue not raised in the pleadings is tried by the parties' express or implied consent, it must be treated in all respects as if raised in the pleadings. A party may move-at any time, even after judgment-to amend the pleadings to conform them to the evidence and to raise an unpleaded issue. But failure so to amend does not affect the result of the trial of that issue. (b)(2) If, at trial, a party objects that evidence is not within the issues raised in the pleadings, the court may permit the pleadings to be amended. The court should freely permit an amendment when doing so will aid in presenting the merits and the objecting party fails to satisfy the court that the evidence would prejudice that party's action or defense on the merits. The court may grant a continuance to enable the objecting party to meet the evidence.(c) Relation back of amendments. An amendment to a pleading relates back to the date of the original pleading when: (c)(1) the law that provides the applicable statute of limitations allows relation back; (c)(2) the amendment asserts a claim or defense that arose out of the conduct, transaction, or occurrence set forth out-or attempted to be set out-in the original pleading; or (c)(3) the amendment adds a party, substitutes a party, or changes the name of the party against whom a claim is asserted, if paragraph (c)(2) is satisfied and if, within the period provided by Rule 4(b) for serving the summons and complaint, the party to be brought in by amendment:(c)(3)(A) received such notice of the action that it will not be prejudiced in defending on the merits; and(c)(3)(B) knew or should have known that the action would have been brought against it, but for a mistake concerning the proper party's identity.(d) Supplemental pleadings. On motion and reasonable notice, the court may, on just terms, permit a party to file a supplemental pleading setting out any transaction, occurrence, or event that happened after the date of the pleading to be supplemented. The court may permit supplementation even though the original pleading is defective in stating a claim or defense. The court may order that the opposing party respond to the supplemental pleading within a specified time.Amended effective November 1, 2016.Advisory Committee Notes
Although the precise language is different for purposes of clarity, the 2016 amendments to Utah Rule of Civil Procedure 15(c) adopt the approach of Federal Rule 15(c) regarding the relation-back of an amended pleading when the amended pleading adds a new party.