A OneTime Showing Agreement form is a legally binding agreement between the buyer's broker and the homeowner listing the property for sale. A One Time Showing Agreement is a commission agreement signed between a buyer's agent and a seller for specific named buyers.A listing agreement is a contract between homeowners and brokers that legally establishes how a realtor will find a property buyer on the seller's behalf. Here to walk you through listing contracts like the contract 101. Forms are state specific because real estate laws vary significantly from state to state.