Cal. CCP § 2035.030

(a) One who desires to perpetuate testimony or preserve evidence for the purposes set forth in Section 2035.010 shall file a verified petition in the superior court of the county of the residence of at least one expected adverse party, or, if no expected adverse party is a resident of the State of California, in the superior court of a county where the action or proceeding may be filed.

(b) The petition shall be titled in the name of the one who desires the perpetuation of testimony or the preservation of evidence. The petition shall set forth all of the following:

(1) The expectation that the petitioner or the petitioner’s successor in interest will be a party to an action cognizable in a court of the State of California.

(2) The present inability of the petitioner and, if applicable, the petitioner’s successor in interest either to bring that action or to cause it to be brought.

(3) The subject matter of the expected action and the petitioner’s involvement. A copy of any written instrument the validity or construction of which may be called into question, or which is connected with the subject matter of the proposed discovery, shall be attached to the petition.

(4) The particular discovery methods described in Section 2035.020 that the petitioner desires to employ.

(5) The facts that the petitioner desires to establish by the proposed discovery.

(6) The reasons for desiring to perpetuate or preserve these facts before an action has been filed.

(7) The name or a description of those whom the petitioner expects to be adverse parties so far as known.

(8) The name and address of those from whom the discovery is to be sought.

(9) The substance of the information expected to be elicited from each of those from whom discovery is being sought.

(c) The petition shall request the court to enter an order authorizing the petitioner to engage in discovery by the described methods for the purpose of perpetuating the described testimony or preserving the described evidence.