New York Consolidated Laws, Uniform District Court Act - UDC § 1814-A. Designation of defendant;  amendment procedure

(a) A party who is ignorant, in whole or in part, of the true name of a person, partnership, firm or corporation which may properly be made a party defendant, may proceed against such defendant in any name used by the person, partnership, firm or corporation in conducting business, as defined in subdivision (a) of section eighteen hundred thirteen-A of this article.

(b) If the true name of the defendant becomes known at any time prior to the hearing on the merits, such information shall be brought to the attention of the clerk, who shall immediately amend all prior proceedings and papers.  The clerk shall send an amended notice to the defendant, without payment of additional fees by the plaintiff, and all subsequent proceedings and papers shall be amended accordingly.

(c) In every action in the commercial claims part, at the hearing on the merits, the judge or arbitrator shall determine the defendant's true name.  The clerk shall amend all prior proceedings and papers to conform to such determination, and all subsequent proceedings and papers shall be amended accordingly.

(d) A party against whom a judgment has been entered pursuant to this article, in any proceeding under section five thousand fifteen of the civil practice law and rules for relief from such judgment, shall disclose its true name;  any and all names in which it is conducting business;  and any and all names in which it was conducting business at the time of the transaction or occurrence on which such judgment is based.  All subsequent proceedings and papers shall be amended to conform to such disclosure.