A One Time Showing Agreement is a commission agreement signed between a buyer's agent and a seller for specific named buyers. Initial Registration.To register a rental property for the first time, complete and submit the following forms: 1. A OneTime Showing Agreement form is a legally binding agreement between the buyer's broker and the homeowner listing the property for sale. Use this form to apply for exemption from the Rent Adjustment Program. This form already includes the required Notice to Tenants and Proof of Service. You must print the forms once you have filled them in. Let your clients in the door faster - with quick access and real-time information available in an easy-to-use app from Supra, real estate industry leaders. The seller must complete Form 593-L, "Real Estate. Withholding-Computation of Estimated Gain or Loss.