Prob. Code, § 4406

(a) If a third person to whom a properly executed statutory form power of attorney under this part is presented refuses to honor the agent’s authority under the power of attorney within a reasonable time, the third person may be compelled to honor the agent’s authority under the power of attorney in an action brought against the third person for this purpose, except that the third person may not be compelled to honor the agent’s authority if the principal could not compel the third person to act in the same circumstances.

(b) If an action is brought under this section, the court shall award attorney’s fees to the agent if the court finds that the third person acted unreasonably in refusing to accept the agent’s authority under the statutory form power of attorney.

(c) For the purpose of subdivision (b), and without limiting any other grounds that may constitute a reasonable refusal to accept an agent’s authority under a statutory form power of attorney, a third person shall not be deemed to have acted unreasonably in refusing to accept an agent’s authority if the refusal is authorized or required by state or federal statute or regulation.

(d) Notwithstanding subdivision (c), a third person’s refusal to accept an agent’s authority under a statutory form power of attorney under this part shall be deemed unreasonable if the only reason for the refusal is that the power of attorney is not on a form prescribed by the third person to whom the power of attorney is presented.

(e) The remedy provided in this section is cumulative and nonexclusive.