California Code, Probate Code - PROB § 1901

(a) The court may by order determine whether the conservatee has the capacity to enter into a valid marriage, as provided in Part 1 (commencing with Section 300) of Division 3 of the Family Code, or to enter into a registered domestic partnership, as provided in Section 297 of the Family Code, at the time the order is made.

(b) A petition for an order under this section may be filed by the conservator of the person or estate or both, the conservatee, any relative or friend of the conservatee, or any interested person.

(c) Notice of the hearing on the petition shall be given for the period and in the manner provided in Chapter 3 (commencing with Section 1460) of Part 1.