A simple model for a letter of reference to be signed by previous landlord and given to tenant who's relocating elsewhere.
To Whom it May Concern:
Please be informed that Tenant(s) Name(s) have been tenants of my apartment/house in New York/elsewhere since Start date of lease. During that time they have been good tenants in that they always kept their apartment neat and clean, were considerate of her neighbors and paid their rent on time. We anticipate full refund of their security deposit.
Please feel free to call me at phone number or write me at Email address if you'd like additional information regarding their desirability as a tenants in one of your properties.