Section 3087 Of Chapter 4. Joint Custody From California Family Law Code >> Division 8. >> Part 2. >> Chapter 4.

. An order for joint custody may be modified or terminated upon the petition of one or both parents or on the court's own motion if it is shown that the best interest of the child requires modification or termination of the order. If either parent opposes the modification or termination order, the court shall state in its decision the reasons for modification or termination of the joint custody order.