N.Y. Comp. Codes R. & Regs. tit. 9, § 2203.4
Where, since the filing of the registration statement for any housing accommodation, there has been a change in the identity of the landlord, by transfer of title or otherwise, and no notice of such change has been filed, the successor landlord shall file a notice, on a form provided for that purpose, on or before June 1, 1962, or within 15 days after the change, whichever is later.