California Code, Code of Civil Procedure - CCP § 996.110

(a) A surety on a bond given in an action or proceeding may at any time apply to the court for an order that the surety be released from liability on the bond.

(b) The principal on a bond may, if a surety applies for release from liability on a bond, apply to the court for an order that another surety be substituted for the original surety.

(c) The applicant shall serve on the principal or surety (other than the applicant) and on the beneficiary a copy of the application and a notice of hearing on the application. Service shall be made not less than 15 days before the date set for hearing.