Civil Code § 3399

3399.

When, through fraud or a mutual mistake of the parties, or a mistake of one party, which the other at the time knew or suspected, a written contract does not truly express the intention of the parties, it may be revised on the application of a party aggrieved, so as to express that intention, so far as it can be done without prejudice to rights acquired by third persons, in good faith and for value.