California Code, Code of Civil Procedure - CCP § 700.050

(1) If the writ of execution is directed to the levying officer having custody of the property, the judgment creditor shall deliver the writ to the levying officer.

(2) If the writ of execution is directed to a levying officer other than the levying officer having custody of the property, the levying officer to whom the writ is directed shall serve a copy of the writ and a notice of levy on the levying officer having custody. Service shall be made personally or by mail.