N.Y. Comp. Codes R. & Regs. tit. 9 § 2102.8
Where all tenants occupying a housing accommodation on June 19, 1997 have permanently vacated such housing accommodation, and a primary-resident family member of such vacating tenant or tenants (first successor) is entitled to and continues to occupy the housing accommodation subject to the protection of this Subchapter, as provided in section 2104.6 of this Title, and thereafter permanently vacates the housing accommodation, if such accommodation continues to be subject to the act and this Subchapter after such family member vacates, and a primary-resident family member (second successor) is entitled to and continues to occupy the housing accommodation subject to the protections of this Subchapter, as provided in section 2104.6 of this Title, the maximum collectible rent shall be increased by a sum equal to the allowance then in effect for vacancy leases for housing accommodations subject to the Rent Stabilization Law of 1969, including the amount allowed by paragraph 5-a of subdivision c of section 26-511 of such law. Such increase shall be in addition to any other increases provided for in this Subchapter, including adjustments pursuant to section 2102.3 of this Part, and shall be applicable in like manner to the maximum collectible rent that may be charged each second subsequent succeeding family member.
N.Y. Comp. Codes R. & Regs. Tit. 9 § 2102.8