A power of appointment is exercised only: (1) If the instrument exercising the power is valid under applicable law; (2) If the terms of the instrument exercising the power: (a) Manifest the powerholder's intent to exercise the power; and (b) Subject to KRS 390.150, satisfy the requirements of exercise, if any, imposed by the donor; and (3) To the extent the appointment is a permissible exercise of power.