N.Y. CVP Law § 1007

§ 1007. When third-party practice allowed. (a) After the service of a\ndefendant's answer, the defendant may proceed against a person or legal\nentity not a party who is or may be liable to that defendant for all or\npart of the plaintiff's claim against that defendant, by filing pursuant\nto section three hundred four of this chapter a third-party summons and\ncomplaint with the clerk of the court in the county in which the main\naction is pending, for which a separate index number shall not be issued\nbut a separate index number fee shall be collected. The third-party\nsummons and complaint and all prior pleadings served in the action shall\nbe served upon such person or legal entity within twenty days of the\nfiling. A defendant serving a third-party complaint shall be styled a\nthird-party plaintiff and the person or legal entity so served shall be\nstyled a third-party defendant. The defendant shall also serve a copy of\nsuch third-party complaint upon the plaintiff's attorney simultaneously\nupon issuance for service of the third-party complaint on the\nthird-party defendant.\n (b) A defendant shall not file a third-party summons and complaint\nmore than ninety days after serving its answer without an order of the\ncourt.\n (c) No third-party summons and complaint may be filed after the filing\nof a note of issue unless upon good cause shown or in the interest of\njustice.\n (d) An action filed in violation of this subdivision shall be severed\nor dismissed without prejudice.\n (e) Notwithstanding subdivisions (b) and (c) of this section, a\ndefendant or third-party defendant may file a third-party summons and\ncomplaint against an employer of the plaintiff without an order of the\ncourt within ninety days after the later of: 1. the date the identity of\nthe employer of the plaintiff becomes known to the defendant or\nthird-party defendant, or 2. the date the defendant or third-party\ndefendant knows or should know the plaintiff sustained a grave injury,\nas such term is defined in section eleven of the workers' compensation\nlaw.\n (f) In the event a third-party action is severed from the initial\naction pursuant to this section, and a third-party plaintiff proceeds to\ninitiate a new action by the filing of a summons and complaint against a\nsevered third-party defendant, any motion to consolidate such actions\nshall not be permitted.\n