Ariz. R. Civ. P. 17

As amended through December 8, 2021
Rule 17 - Plaintiff and Defendant; Capacity; Public Officers
(a) Real Party in Interest.
(1)Designation Generally. An action must be prosecuted in the name of the real party in interest. The following may sue in their own names without joining the person for whose benefit the action is brought:
(A) a personal representative or executor;
(B) an administrator;
(C) a guardian;
(D) a bailee;
(E) a trustee of an express trust;
(F) a party with whom or in whose name a contract has been made for another's benefit; and
(G) a party authorized by statute.
(2)Action in the Name of the State for Another's Use or Benefit. When a state statute so provides, an action for another's use or benefit must be brought in the name of the State of Arizona.
(3)Joinder of the Real Party in Interest. The court may not dismiss an action for failure to prosecute in the name of the real party in interest until, after an objection, a reasonable time has been allowed for the real party in interest to ratify, join, or be substituted into the action. After ratification, joinder, or substitution, the action proceeds as if it had been originally commenced by the real party in interest.
(b) Actions by Personal Representatives; Setting Aside Judgment. An executor, administrator, or guardian may commence or maintain any action that the testator or intestate could have commenced or maintained, and an action may be brought against an executor, administrator, or guardian if it could have been brought against the testator or intestate. The judgment in such an action is as conclusive as if it was rendered in favor of or against the testator or intestate. An interested person may apply to set aside the judgment on the ground that it resulted from fraud or collusion by the executor, administrator, or guardian.
(c) Actions by or Against a County, City, or Town. An action brought by or against a county or an incorporated city or town must use its corporate name when identifying it as a party.
(d) Public Officer's Title and Name. A public officer who sues or is sued in an official capacity may be identified as a party by the officer's official title rather than by name, if it is sufficient to identify the particular public officer being sued, but the court may require the officer's name to be used or added to identify the officer as the party.
(e) Actions Against a Surety, Assignor, or Endorser. A plaintiff may sue a contractual assignor, endorser, guarantor, surety, or the drawer of a bill that has been accepted, without joining the maker, acceptor, or other principal obligor if:
(1) the latter resides outside Arizona, or in a part of Arizona where it cannot be served under Rule 4, 4.1, or 4.2;
(2) the latter's residence is unknown and cannot be ascertained through reasonable diligence;
(3) the latter is dead; or
(4) the latter is insolvent.
(f) Minor or Incompetent Person.
(1)With a Representative. The following representatives may sue or defend on behalf of a minor or an incompetent person:
(A) a general guardian;
(B) a conservator; or
(C) a similar fiduciary.
(2)Without a Representative.
(A)Generally. A minor or an incompetent person who does not have a duly appointed representative may sue by a next friend or by a guardian ad litem. The court must appoint a guardian ad litem-or issue another appropriate order-to protect a minor or incompetent person who is unrepresented in an action.
(B)Consent. No person may be appointed guardian ad litem unless that person files a written consent to the appointment.
(C)Bond. If a next friend or guardian ad litem brings an action on behalf of a minor, that person may not receive any of the minor's money or property without filing a bond as security in an amount and under such terms as the court approves.
(D)Liability for Costs. Unless the court orders otherwise, a next friend or guardian ad litem may not be held personally liable for costs.
(E)Compensation. The court may award reasonable compensation to a next friend or a guardian ad litem for their services, which must be taxed as part of the action's costs.
(g) Partnerships. A partnership may sue and be sued in the name that it has adopted or by which it is known.

Ariz. R. Civ. P. 17

Amended effective January 1, 2017.

State Bar Committee Note

1966 Amendment to Rule 17(a)(3)

The provision that no action shall be dismissed on the ground that it is not prosecuted in the name of the real party in interest until a reasonable time has been allowed, after the objection has been raised, for ratification, substitution, etc., is added simply in the interests of justice. In its origin the rule concerning the real party in interest was permissive in purpose: it was designed to allow an assignee to sue in his own name. That having been accomplished, the modern function of the rule in its negative aspect is simply to protect the defendant against a subsequent action by the party actually entitled to recover, and to insure generally that the judgment will have its proper effect as res judicata.

The provision is intended to prevent forfeiture when determination of the proper party to sue is difficult or when an understandable mistake has been made. It does not mean, for example, that, following an airplane crash in which all aboard were killed, an action may be filed in the name of John Doe (a fictitious person), as personal representative of Richard Roe (another fictitious person), in the hope that at a later time the attorney filing the action may substitute the real name of the real personal representative of a real victim, and have the benefit of suspension of the limitation period. It does not even mean, when an action is filed by the personal representative of John Smith, of Buffalo, in the good faith belief that he was aboard the flight, that upon discovery that Smith is alive and well, having missed the fatal flight, the representative of James Brown, of San Francisco, an actual victim, can be substituted to take advantage of the suspension of the limitation period. It is, in cases of this sort, intended to insure against forfeiture and injustice-in short, to codify in broad terms the salutary principle of Levinson v. Deupree, 73 S. Ct. 914, 345 U.S. 648, 97 L. Ed. 1319 (1953), and Link Aviation, Inc. v. Downs, 325 F.2d 613 (D.C. Cir. 1963 ). The amendment does not alter the results of existing Arizona decisions.