(1) Personal appearance of a person in a hearing before the court shall obviate the necessity of serving process upon that person.
(2) Upon the filing of a petition requesting the appointment of a guardian advocate, and upon request of the petitioner, the clerk or deputy clerk shall issue a summons.
(3) The summons shall require the person on whom it is served to appear for a hearing at a time and place specified. Except in cases of medical emergency, the time shall be not less than 24 hours after service of the summons. The summons shall be directed to and shall be served upon the parents. It shall not be necessary to the validity of a proceeding for the appointment of a guardian advocate that the parents be present if their identity or presence is unknown after a diligent search and inquiry have been made, if they have become residents of a state other than this state, or if they evade service or ignore a summons, but in this event the person who made the search and inquiry shall file a certificate of those facts.
(4) Upon the application of a party, the clerk or deputy clerk shall issue, and the court on its own motion may issue, subpoenas requiring attendance and testimony of witnesses and production of records, documents, or other tangible objects at any hearing.