If a power of appointment releasable according to § 45a-568 is or may be exercisable by two or more persons in conjunction with one another or successively, a release or disclaimer of the power, in whole or in part, executed and delivered or filed, in accordance with § 45a-569, by any one of the donees of the power, shall, subject to the provisions of § 45a-569, be effective to release or disclaim, to the extent therein provided, all right of such person to exercise, or to participate in the exercise of, the power, but, unless the instrument creating the power otherwise provides, shall not prevent or limit the exercise or participation in the exercise thereof by the other donee or donees thereof.