California Code, Probate Code - PROB § 453

(a) On petition of a person required to appear before the probate referee pursuant to this chapter, the court may make a protective order to protect the person from annoyance, embarrassment, or oppression.  The petitioner shall deliver pursuant to Section 1215 notice of the hearing on the petition to the probate referee and to the personal representative, guardian, conservator, or other fiduciary at least 15 days before the date set for the hearing.  Any subpoena issued by the probate referee is stayed during the pendency of the petition.

(b) On petition of the probate referee, the court may make an order to show cause why a person who is required, but fails, to appear before the probate referee pursuant to this chapter, should not be compelled to do so.  The probate referee shall deliver pursuant to Section 1215 notice of the hearing on the petition to the person at least 15 days before the date set for the hearing.