California Code, Probate Code - PROB § 1893

(a) Where the conservatee is out of state when served and is not the petitioner.

(b) Where the conservatee is unable to attend the hearing by reason of medical inability established (1) by the affidavit or certificate of a licensed medical practitioner or (2) if the conservatee is an adherent of a religion whose tenets and practices call for reliance on prayer alone for healing and is under treatment by an accredited practitioner of that religion, by the affidavit of the practitioner.  The affidavit or certificate is evidence only of the conservatee's inability to attend the hearing and shall not be considered in determining the issue of the legal capacity of the conservatee.  Emotional or psychological instability is not good cause for the absence of the conservatee from the hearing unless, by reason of such instability, attendance at the hearing is likely to cause serious and immediate physiological damage to the conservatee.

(c) Where the court investigator has reported to the court that the conservatee has expressly communicated that the conservatee (1) is not willing to attend the hearing and (2) does not wish to contest the petition, and the court makes an order that the conservatee need not attend the hearing.