Rules on Civil Procedure
Section 2. Contents of petition. - The petition shall be entitled in the name of the petitioner and shall show: (a) that the petitioner expects to be a party to an action in a court of the Philippines but is presently unable to bring it or cause it to be brought; (b) the subject matter of the expected action and his interest therein; (c) the facts which he desires to establish by the proposed testimony and his reasons for desiring to perpetuate it; (d) the names or a description of the persons he expects will be adverse parties and their addresses so far as known; and (e) the names and addresses of the persons to be examined and the substance of the testimony which he expects to elicit from each, and shall ask for an order authorizing the petitioner to take the depositions of the persons to be examined named in the petition for the purpose of perpetuating their testimony. (2, R134)