The Parties may amend this Contract to attach a complete and correct legal description of the Property. 187. K. Affidavit of Title; ALTA.An Illinois purchase agreement is a standard contract for selling real estate from one party to another. Except as otherwise disclosed in the Property Information, Title Commitment or. (Seller) agrees to sell the real estate and the property described above, if any, at the price and terms set forth herein, and to convey. A purchase and sale agreement is a contract between a buyer and seller for transacting a property in exchange for a specific price.