Section 10-6.4 - Exercise of a power of appointment; required consents(a) When the consent of the donor or of a third person to the exercise of a power of appointment is required, such consent shall be expressed in a written instrument, subscribed by the person whose consent is required; and to entitle the instrument of exercise to be recorded, the signatures of the donee and of the person consenting must be acknowledged or proved in the manner required by the laws of this state for the recording of a deed of real property.(b) Unless the donor expressly provides otherwise:(1) When the consents of two or more persons are required for the exercise of a power of appointment, all must consent.(2) If before the exercise of the power:(A) One or more of such persons die, the consent of the survivor is sufficient.(B) One or more of such persons become incompetent, the consent of the competent person is sufficient.