Cal. Code of Civil Procedure § 2035.040

(a) The petitioner shall cause service of a notice of the petition under Section 2035.030 to be made on each natural person or organization named in the petition as an expected adverse party. This service shall be made in the same manner provided for the service of a summons. (b) The service of the notice shall be accompanied by a copy of the petition. The notice shall state that the petitioner will apply to the court at a time and place specified in the notice for the order requested in the petition. (c) This service shall be effected at least 20 days prior to the date specified in the notice for the hearing on the petition. (d) If after the exercise of due diligence, the petitioner is unable to cause service to be made on any expected adverse party named in the petition, the court in which the petition is filed shall make an order for service by publication. (e) If any expected adverse party served by publication does not appear at the hearing, the court shall appoint an attorney to represent that party for all purposes, including the cross-examination of any person whose testimony is taken by deposition. The court shall order that the petitioner pay the reasonable fees and expenses of any attorney so appointed.