The relation-back doctrine permits the commencement of claims against a party that has not been timely sued, but which relate back to the original timely complaint. A plaintiff must establish all three prongs of a three-part test for the addition of untimely claims or parties: (1) the new claims arise out of the same conduct, transaction, or occurrence as that alleged in the original complaint; (2) the party to be added must be united in interest with one or more of the original defendants, and by reason of that relationship can be charged with such notice of the institution of the action that it will not be prejudiced in defending the action on the merits; and (3) the newly-added defendant knew, or should have known, that the action would have been timely commenced against it but for a mistake by the plaintiff as to the identity of the proper parties.
DiMiceli v. Credit Shelter Trust, NY Slip Op 02391 (2d Dep't April 23, 2026)
