A guarantor guarantees the lease in case the tenant doesn't qualify on their own for a New York City apartment. A second chance to secure your dream home.Helping you qualify for the rental you want, while giving property managers protection against defaults. The lease is countersigned at our office and the unit is yours! Com or ask your property manager about Leap. Cosigners and guarantors sign the lease with you and fulfill the purpose of taking responsibility for the monthly rent. Draft CoSign Lease Form A lease guarantor form should be presented to the tenant and guarantor for review. Landlord owns certain real property and improvements located at. (hereinafter referred to as the "Property"). JOINT LIABILITY LEASE CONTRACT: A joint liability interest in the apartment numbered ______, located at 2060 N. High St., Columbus,.