Probate Code § 642

642.

If a power of appointment existing at the powerholder’s death, but created after the execution of the powerholder’s will, is exercised by the will, the appointment is effective except in either of the following cases:

(a) The creating instrument manifests an intent that the power may not be exercised by a will previously executed.

(b) The will manifests an intent not to exercise a power subsequently acquired.