A Commission Agreement for Sale is used for one-time showings of real estate so a Realtor can show a home to a prospective buyer and be paid a commission. The listing agent will execute with the Seller a Listing Agreement such as the ERS20tb.A One Time Showing Agreement is a commission agreement signed between a buyer's agent and a seller for specific named buyers. Below is a list of forms that you may download for free from our website. Completing the listing agreement will take just 20 to 30 minutes if done correctly.