Cal. GOV § 11184

(a) In any hearing in any part of the state or in any investigation conducted under this article, the head of the department shall issue process and subpoenas in a manner consistent with the California Constitution and the United States Constitution, and the process and subpoenas shall be served in the same manner as provided for the service of a summons as described in Chapter 4 (commencing with Section 413.10) of Title 5 of Part 2 of the Code of Civil Procedure. Service of process and subpoenas may be effectuated by any person designated for that purpose by the head of the department. The person serving any process or a subpoena may receive compensation as is allowed by the head of the department not to exceed the fees prescribed by law for similar service. This compensation shall be paid in the manner provided in this article for the payment of the fees of witnesses.

(b) If the subpoena requires oral testimony from a witness who is not a natural person, the subpoena shall describe, with reasonable particularity, the matters on which examination is requested. In that event, the subpoenaed witness shall designate and produce at the hearing those natural persons who are most qualified to testify on behalf of the subpoenaed witness about those matters to the extent of any information known or reasonably available to the subpoenaed witness. The subpoena shall notify the witness named in the subpoena of its duty to designate and produce natural persons to testify as described in this subdivision.