CIV §1689: (a) A contract may be rescinded if all the parties thereto consent.

(a) A contract may be rescinded if all the parties thereto consent. (b) A party to a contract may rescind the contract in the following cases: (1) If the consent of the party rescinding, or of any party jointly contracting with him, was given by mistake, or obtained through duress, menace, fraud, or undue influence, exercised by or with the connivance of the party as to whom he rescinds, or of any other party to the contract jointly interested with such party. (2) If the consideration for the obligation of the rescinding party fails, in whole or in part, through the fault of the party as to whom he rescinds. (3) If the consideration for the obligation of the rescinding party becomes entirely void from any cause. (4) If the consideration for the obligation of the rescinding party, before it is rendered to him, fails in a material respect from any cause. (5) If the contract is unlawful for causes which do not appear in its terms or conditions, and the parties are not equally at fault. (6) If the public interest will be prejudiced by permitting the contract to stand. (7) Under the circumstances provided for in Sections 39, 1533, 1566, 1785, 1789, 1930 and 2314 of this code, Section 2470 of the Corporations Code, Sections 331, 338, 359, 447, 1904 and 2030 of the Insurance Code or any other statute providing for rescission.