Cal. Civ. Proc. Code § 262

The direction or authority of a party or his or her attorney to a sheriff, in respect to the execution of process or return thereof, or to any related act or omission, is not available to discharge or excuse the sheriff from a liability for neglect or misconduct, unless it is contained in written instructions by the attorney of the party, including the signature and name of the attorney of the party, or by the party, if he or she has no attorney. Subject to subdivision (c) of Section 263, the instructions may be transmitted electronically pursuant to Chapter 2 (commencing with Section 263).