Rule 28.Amended and Supplemental Pleadings

Part II. Pleadings and Motions · Last amended January 1, 2019 · Last verified September 4, 2026

In one sentenceRule 28 allows one amendment as a matter of right, requires a redlined copy of any proposed amended pleading, and lets amendments relate back to the original pleading's date when they arise from the same conduct or occurrence.

Full Text of Rule 28

Text sizeJump to: (a) (b) (c) (d)

(a) Amendments Before Trial.

(1) Amending as a Matter of Right. A party may amend its pleading once as a matter of right

(A) at any time before a responsive pleading is served, or

(B) if the pleading is one to which no responsive pleading is required, and no hearing has been set, the party may amend it at any time within 20 days after it was served.

(2) Amending by Leave of Court. A party who cannot amend under Rule 28(a)(1) may amend by written agreement of all parties or may request the court's permission to amend. Leave to amend will be freely given when justice requires.

(3) Proposed Pleading as an Exhibit. A party moving for leave to amend a pleading must attach a copy of the proposed amended pleading as an exhibit to the motion. The exhibit must show how the proposed pleading differs from the existing pleading by bracketing or striking through the text to be deleted and underlining the text to be added.

(4) Filing and Response. If a motion for leave to amend is granted, the moving party must file and serve the amended pleading within 10 days after the entry of the order granting the motion, unless the court orders otherwise. An opposing party must respond to an amended pleading, if a response is required, within the time remaining for response to the original pleading or within 10 days after the amended pleading is served, whichever is later, unless the court orders otherwise.

(b) Amendments During and After Trial.

(1) Based on an Objection at Trial. 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 may grant a continuance to enable the objecting party to respond to the evidence.

(2) For Issues Tried by Consent. When an issue not raised by the pleadings is introduced at trial by the parties' express or implied consent, it must be treated in all respects as if it had been raised in the pleadings. A party may request, at any time, to amend the pleadings to conform to the evidence. Failure to amend does not affect the result of the trial of that issue.

(c) Relation Back of Amendments. An amendment relates back to the date of the original pleading if the amendment asserts a claim or defense that arose out of the conduct, transaction, or occurrence set forth, or attempted to be set forth, in the original pleading.

(d) Supplemental Pleadings. On motion and reasonable notice, the court may permit a party to file a supplemental pleading setting forth any transaction, occurrence, or event that happened after the date of the pleading to be supplemented. A court may permit supplementation even though the original pleading is defective in stating a claim for relief or defense. The court may order the opposing party to answer or otherwise respond to the supplemental pleading within a specified time.

End

Rule History

Added Aug. 30, 2018, effective Jan. 1, 2019.

Plain-English Summary

Rule 28 governs changing a pleading after it is filed -- before trial, during trial, and after events that postdate the pleading altogether.

Before trial

A party may amend once as a matter of right at any time before a responsive pleading is served. Where no responsive pleading is required and no hearing has been set, the party may amend within 20 days after the pleading was served. Beyond that, amendment requires written agreement of all parties or the court's permission, and leave will be freely given when justice requires.

The exhibit requirement

Subpart (a)(3) is a formatting rule with teeth. A motion for leave to amend must attach the proposed amended pleading as an exhibit, showing how it differs from the existing pleading by bracketing or striking through deleted text and underlining added text. The court is entitled to see the change, not just the result.

If leave is granted, the amended pleading must be filed and served within 10 days after entry of the order. An opposing party responds within the time remaining on the original pleading or within 10 days after the amended pleading is served, whichever is later.

During and after trial

If a party objects at trial that evidence falls outside the pleadings, the court may permit amendment and may grant a continuance so the objecting party can meet the evidence. And where an unpleaded issue is tried by express or implied consent, it must be treated in all respects as if it had been pleaded -- a party may move to amend to conform at any time, and failure to amend does not affect the result.

Relation back, and supplements

An amendment relates back to the date of the original pleading if it asserts a claim or defense arising out of the conduct, transaction or occurrence set forth, or attempted to be set forth, in the original. Separately, section (d) allows a supplemental pleading covering events that happened after the pleading being supplemented -- available on motion and reasonable notice, and available even if the original pleading was defective.

Frequently Asked Questions

Can I amend my petition without asking the court?

Once. Rule 28(a)(1) allows amendment as a matter of right at any time before a responsive pleading is served, or -- where no responsive pleading is required and no hearing has been set -- within 20 days after the pleading was served.

What has to be attached to a motion for leave to amend?

Rule 28(a)(3) requires a copy of the proposed amended pleading as an exhibit, marked to show how it differs from the existing pleading: deleted text bracketed or struck through, added text underlined.

What standard does the court apply to a request to amend?

Rule 28(a)(2) says leave to amend will be freely given when justice requires.

An issue was tried that nobody pleaded. Does that matter?

Rule 28(b)(2) treats an issue introduced by the parties' express or implied consent as if it had been raised in the pleadings, and says failure to amend does not affect the result of the trial of that issue.

What is the difference between an amended and a supplemental pleading?

An amendment changes what was pleaded about events that had already occurred. A supplemental pleading under Rule 28(d) sets out a transaction, occurrence or event that happened after the date of the pleading being supplemented, and requires a motion and reasonable notice.

When does an amendment count as filed on the original date?

Rule 28(c) relates an amendment back when it asserts a claim or defense arising out of the conduct, transaction or occurrence set forth, or attempted to be set forth, in the original pleading.

Source & verification. Rule text and Rule History reproduced verbatim from the Arizona Rules of Family Law Procedure as published by the Arizona Supreme Court, current through amendments effective January 1, 2026. Promulgated by the Supreme Court of Arizona (Ariz. Const. art. 6, § 5). Last verified September 4, 2026. · Official text

Also known as: amending a petitionamended pleadingleave to amendrelation backsupplemental pleadingredlinetried by consent