Section 630 Of Article 2. Scope Of Donee’s Authority From California Probate Code >> Division 2. >> Part 14. >> Chapter 4. >> Article 2.

. (a) Except as otherwise provided in this part, if the creating instrument specifies requirements as to the manner, time, and conditions of the exercise of a power of appointment, the power can be exercised only by complying with those requirements.
  (b) Unless expressly prohibited by the creating instrument, a power stated to be exercisable by an inter vivos instrument is also exercisable by a written will.