California Code, Probate Code - PROB § 4206

(a) If, following execution of a durable power of attorney, a court of the principal's domicile appoints a conservator of the estate, guardian of the estate, or other fiduciary charged with the management of all of the principal's property or all of the principal's property except specified exclusions, the attorney-in-fact is accountable to the fiduciary as well as to the principal. Except as provided in subdivision (b), the fiduciary has the same power to revoke or amend the durable power of attorney that the principal would have had if not incapacitated, subject to any required court approval.

(b) If a conservator of the estate is appointed by a court of this state, the conservator can revoke or amend the durable power of attorney only if the court in which the conservatorship proceeding is pending has first made an order authorizing or requiring the fiduciary to modify or revoke the durable power of attorney and the modification or revocation is in accord with the order.

(c) This section is not subject to limitation in the power of attorney.