Complete and review the Listing Agreement with the sellers. 6. Have sellers fill out the Property Information Disclosure form. 7.A listing agreement is a legally binding contract between a homeowner and the real estate agent or broker who will be listing the property for sale. Sellers guardian a licensed real estate agent in the state of Washington. The Seller agrees to complete and provide information to the best of their ability with true, factual, and accurate information. The. Signing a Listing Agreement in Washington.