N.Y. Real Property Law § 227-C
(c) Within twenty-five days of such notice, the tenant shall provide documentation demonstrating that the tenant or a member of the tenant's household has been a victim of domestic violence as described in subdivision one of this section. This documentation may include any one or more of the following:
(iv) A written verification from any other qualified third party to whom the tenant, or a member of the tenant's household reported the domestic violence.
4. Co-tenants and other occupants. Upon termination:
(a) If the terminating tenant is the sole leaseholder, the premises shall be delivered to the lessor or owner:
(b) If there are tenants on the lease other than the terminating tenant: