N.Y. Comp. Codes R. & Regs. tit. 9, § 2521.3 – Classification of buildings.

(a) Upon application by a tenant or owner, the DHCR shall issue an order determining a building's classification based upon the services provided and other relevant factors. Except as provided in subdivisions (c) and (d) of this section, if it is determined that such building is not a hotel, the DHCR shall classify the building as an apartment building unless the owner restores sufficient services to maintain a hotel classification in accordance with subdivision (b) of this section. If the building is reclassified, then the housing accommodations therein shall thereafter be subject to the provisions of this Code applicable to apartment buildings, at the legal regulated rent for each housing accommodation as determined by the order of the DHCR, plus lawful increases and adjustments allowed pursuant to this Code. In order for an owner to retain or continue the building's classification as a hotel, he or she must provide, in addition to any other services he or she is or was providing pursuant to section 2520.6(r) of this Title, all four of the following services:
1. (1) maid service, consisting of general housecleaning at a frequency of at least once a week;
2. (2) linen service, consisting of providing clean linens at a frequency of at least once a week;
3. (3) furniture and furnishings, including at a minimum a bed, lamps, storage facilities for clothing, chair and mirror in a bedroom; such furniture to be maintained by the hotel owner in reasonable condition; and
4. (4) lobby staffed 24 hours a day, seven days a week by at least one employee.
(b) A building's classification as a hotel will not be retained or continued where the DHCR determines that 51 percent of the permanent tenants are not receiving maid and linen service, except that all tenants receiving such services shall be entitled to receive the services for the duration of their occupancy. Where an owner is providing maid and linen service to 51 percent of the permanent tenants and the owner wishes to maintain the building's classification as a hotel, the owner shall be afforded 90 days to restore all four hotel services described above, without any additional rent increase for such services, to all of the building's permanent tenants, except that those tenants whose housing accommodations were rented to them as apartment (not hotel) housing accommodations shall have the option of rejecting restoration of hotel services and be subject to the RSL, pursuant to the provisions of this Code applicable to apartment buildings, until they vacate, at which time the owner shall be required to restore hotel services to the housing accommodations.
(c) Notwithstanding the provisions of subdivision (a) of this section, single-room occupancy facilities such as single-room occupancy hotels or rooming houses, as defined in the MDL, shall not be subject to reclassification pursuant to this section. However, such housing accommodations shall be included in the definition of hotel as set forth in section 2520.6(b) of this Title for all other purposes of this Code, except that the four minimum services enumerated in such section shall not be required to be provided unless such services were provided on the applicable base dates pursuant to section 2520.6(r)(4) of this Title.
(d) Notwithstanding the provisions of subdivision (a) of this section, the DHCR may decline to reclassify a hotel to apartment building status if it finds that the owner has reduced any of the four hotel services listed in such subdivision (a) for the purpose of reclassification of the building.