Pursuant to CPLR 1003, "[p]arties may be added at any stage of [an] action by leave of court or by stipulation of all parties who have appeared." Pursuant to CPLR 3025(b), a party may amend or supplement its pleading by setting forth additional or subsequent transactions or occurrences, at any time by leave of court or by stipulation of all parties. A plaintiff's failure to comply with CPLR 1003 when attempting to add a defendant is a jurisdictional defect, and an amended complaint that is not filed in accordance with CPLR 1003 and 3025 is a legal nullity, warranting dismissal.
Bodkin v. 112 Automative Ctr., Inc., NY Slip 01074 (2d Dep't March 1, 2023)
