Cal. CIV § 2322

An authority expressed in general terms, however broad, does not authorize an agent to do any of the following: (a) Act in the agent’s own name, unless it is the usual course of business to do so. (b) Define the scope of the agency. (c) Violate a duty to which a trustee is subject under Section 16002, 16004, 16005, or 16009 of the Probate Code.