1, the real estate license is the name of two people. In principle, the sales contract should be signed by two property owners respectively, and the contract is valid. 2. The real estate license is the name of two people, and there are cases where one person signs it, including: (1) If one of the property owners obtains the power of attorney from another property owner, he has the right to buy and sell the relevant house on his behalf, and the contract can be signed by an authorized property owner. (2) If one property owner fails to obtain the power of attorney from the other property owner, but the buyer has reason to believe that he has the right to sell the house and pay a reasonable price, the contract is valid. (3) If one party's property owner sells the property without the consent of the other party's property owner, and after one party signs it, the other party's property owner ratifies the consent, the contract is valid.