Cal. PROB § 633

(a) If the creating instrument requires the consent of the donor or other person to exercise a power of appointment, the power can only be exercised when the required consent is contained in the instrument of exercise or in a separate written instrument, signed in each case by the person whose consent is required. (b) Unless expressly prohibited by the creating instrument: (1) If a person whose consent is required dies, the power may be exercised by the powerholder without the consent of that person. (2) If a person whose consent is required becomes legally incapable of consenting, the person’s guardian or conservator may consent to an exercise of the power. (3) A consent may be given before or after the exercise of the power by the powerholder.