California Code, Family Code - FAM § 3083

In making an order of joint legal custody, the court shall specify the circumstances under which the consent of both parents is required to be obtained in order to exercise legal control of the child and the consequences of the failure to obtain mutual consent. In all other circumstances, either parent acting alone may exercise legal control of the child. An order of joint legal custody shall not be construed to permit an action that is inconsistent with the physical custody order unless the action is expressly authorized by the court.