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. Today we are going to be going over a very simple form but a very important one the extension addendum to contract.The new law is we can no longer force sellers to pay commsion to the buyer's hired agent. That was also the old law, but brokers ignored it. Detailed information about canceling listing agreements and contracts, calculating time periods and other common real estate scenarios. PSA TO ALL HOME BUYERS: On August 17th a Realtor CAN NOT show you a home unless you have signed agreement with them. A One Time Showing Agreement is a commission agreement signed between a buyer's agent and a seller for specific named buyers. How to Fill Out a Listing Agreement- Florida Realtor. Page 11 of 65 time established. Real estate agents commonly use standardized, fill-in-the-blank forms that cover all the bases, including the ones described in this article.