Subject to the approval of the court, any beneficiary, if of full age and not an incapacitated person, may, if acting upon full information, by written instrument delivered to the trustee, excuse the trustee as to such beneficiary from performing any of the duties imposed on the trustee by this article or exempt the trustee from liability to such beneficiary for failure to perform any of the duties imposed upon the trustee by the terms of this article.
K.S.A. 59-1608