(a) Amended pleadings. A party may amend his pleading once as a matter of course at any time before a responsive pleading is served or, if the pleading is one to which no responsive pleading is permitted and the action has neither been placed upon the trial calendar, nor an order made setting a date for trial, he may so amend it at any time within twenty days after it is served. Otherwise a party may amend his pleading only by leave of court or by written consent of the adverse party; and leave shall be freely given when justice so requires. A party shall plead in response to an amended pleading within the time remaining for response to the original pleading or within ten days after service of the amended pleading, whichever period may be the longer, unless the court otherwise orders.
Rule 15.Amended and Supplemental Pleadings
Part III: Pleadings and Motions · Last amended 1969 · Last verified July 16, 2026
In one sentenceRule 15-6-15 sets when a party may amend a pleading as a matter of course versus by leave of court, allows pleadings to conform to issues tried even without a formal amendment, and lets amendments relate back to the original pleading’s filing date under specific conditions, along with a separate procedure for supplemental pleadings covering later events.
Full Text of Rule 15-6-15
(b) Trial of issues not raised by pleadings. When issues not raised by the pleadings are tried by express or implied consent of the parties, they shall be treated in all respects as if they had been raised in the pleadings. Such amendment of the pleadings as may be necessary to cause them to conform to the evidence and to raise these issues may be made upon motion of any party at any time, even after judgment; but failure so to amend does not affect the result of the trial of these issues. If evidence is objected to at the trial on the ground that it is not within the issues made by the pleadings, the court may allow the pleadings to be amended and shall do so freely when the presentation of the merits of the action will be subserved thereby and the objecting party fails to satisfy the court that the admission of such evidence would prejudice him in maintaining his action or defense upon the merits. The court may grant a continuance to enable the objecting party to meet such evidence.
(c) Amendments as relating back to pleadings. Whenever the claim or defense asserted in the amended pleading arose out of the conduct, transaction or occurrence set forth or attempted to be set forth in the original pleading, the amendment relates back to the date of the original pleading. An amendment changing the party against whom a claim is asserted relates back if the foregoing provision is satisfied and, within the period provided by law for commencing the action against him, the party to be brought in by amendment:
(1) has received such notice of the institution of the action that he will not be prejudiced in maintaining his defense on the merits; and
(2) knew or should have known that, but for a mistake concerning the identity of the proper party, the action would have been brought against him.
(d) Supplemental pleading. 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 or occurrences or events which have happened since the date of the pleading sought to be supplemented. Permission may be granted even though the original pleading is defective in its statement of a claim for relief or defense. If the court deems it advisable that the adverse party plead to the supplemental pleading, it shall so order, specifying the time therefor.
Plain-English Summary
Rule 15-6-15 gives pleadings flexibility to change as a case develops. Subdivision (a) allows one amendment as a matter of course, without needing permission, before a responsive pleading is served, or, if no response is permitted and the case has not yet been set for trial, within twenty days after the pleading was served. Beyond that, a party needs leave of court or the other side’s written consent, and courts are directed to give that leave freely when justice requires it. A party responding to an amended pleading gets whichever is longer: the time remaining to respond to the original pleading, or ten days after the amendment was served.
Subdivision (b) deals with the gap between what the pleadings say and what gets litigated at trial. If the parties try an issue not raised in the pleadings, whether by express or implied consent, the rule treats it as if it had been pleaded all along, and the pleadings can be amended to match even after judgment, though failure to amend does not undo the trial of that issue. If a party objects that evidence falls outside the pleaded issues, the court may allow amendment anyway and should do so freely when it would serve the merits and the objecting party cannot show real prejudice, granting a continuance if needed to let that party respond to the new evidence.
Subdivision (c) lets an amendment relate back to the date of the original pleading when the new claim or defense arises from the same conduct, transaction, or occurrence already set out or attempted to be set out. An amendment that changes the party against whom a claim is asserted relates back the same way if, in addition, the new party received notice of the action in time to avoid prejudice to their defense and knew or should have known the action would have named them but for a mistake about identity. Subdivision (d) covers a different situation: supplemental pleadings addressing events that happened after the original pleading was filed, which the court may permit on reasonable notice and terms, even if the original pleading itself was defective.
Frequently Asked Questions
Can I amend my complaint without asking the court’s permission?
Yes, once. Rule 15-6-15(a) allows one amendment as a matter of course before a responsive pleading is served, or within twenty days of service if no response is permitted and the case has not been set for trial. After that, amendment requires leave of court or the other party’s written consent.
What if the parties end up trying an issue at trial that wasn’t in the pleadings?
Rule 15-6-15(b) treats an issue tried by express or implied consent as if it had been raised in the pleadings, and the pleadings may be amended to conform to that evidence even after judgment, though failing to amend does not affect the result of the trial on that issue.
When does an amended pleading relate back to the date of the original pleading?
Rule 15-6-15(c) allows relation back when the amended claim or defense arises out of the same conduct, transaction, or occurrence already set out or attempted to be set out in the original pleading.
Can I amend my complaint to correct the name of the defendant I meant to sue?
Yes, under conditions. Rule 15-6-15(c) allows an amendment changing the party against whom a claim is asserted to relate back if the new party received timely notice that avoids prejudice and knew or should have known the action would have named them but for a mistake about identity.
What is a supplemental pleading and how is it different from an amended one?
Rule 15-6-15(d) describes a supplemental pleading as one that sets out transactions, occurrences, or events happening after the original pleading was filed. The court may permit it on reasonable notice and terms, even if the original pleading was itself defective.
Amendment History
(a)SDC 1939 & Supp 1960, § 33.0914; SD RCP, Rule 15 (a), as adopted by Sup. Ct. Order March 29, 1966, effective July 1, 1966.
(b)SDC 1939 & Supp 1960, § 33.0914; SD RCP, Rule 15 (b), as adopted by Sup. Ct. Order March 29, 1966, effective July 1, 1966.
(c)SD RCP, Rule 15 (c), as adopted by Sup. Ct. Order March 29, 1966, effective July 1, 1966; as amended by Sup. Ct. Order No. 2, March 31, 1969, effective July 1, 1969.
(d)SDC 1939 & Supp 1960, § 33.0913; SD RCP, Rule 15 (d), as adopted by Sup. Ct. Order March 29, 1966, effective July 1, 1966.
Source & verification. Rule text and History are
reproduced verbatim from the South Dakota Codified Laws, published by the
South Dakota Legislative Research Council. Last verified July 16, 2026.
· Official source
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