N.Y. Multiple Residence Law § 325
3. Each county board shall have power within its county, except as stated to the contrary in subdivision eight of this section, and each local board of review, as provided in said subdivision eight, shall have power within its own applicable area: a. With respect to dwellings existing on the effective date of this chapter only, to vary or modify, in whole or in part, the application of any provision of this chapter or of any rule or regulation of the department or commission, relating and limited to