For the assignment of a sales contract to be valid, the contracting authority and the transferor must first have a valid legal contract attesting that the transferor is required to purchase a house or condo from the contracting authority. When drafting contract documentation, there are questions that should be asked to determine liability. Some of the questions to ask are: While your company (BUYER) __ has entered into a purchase and sale agreement with Sallie Jane (SELLER) __ for the purchase of SUBJECT PROPERTY______________________ and the buyer wishes to assign its rights, interests and obligations in the purchase and sale agreement, this is agreed between the buyer and the buyer as follows: The assignment or assignment of a contract is a document, which allows one party to transfer the rights and benefits of a contract to another party. .