A beneficiary of a trust affected by AS 13.36.105 - 13.36.220 may, if the beneficiary has full legal capacity and acts on full information, by written instrument delivered to the trustee, relieve the trustee, as regards the beneficiary, from any or all of the duties, restrictions, and liabilities that would otherwise be imposed on the trustee by AS 13.36.105 - 13.36.220, except for the duties, restrictions, and liabilities imposed by AS 13.36.140 - 13.36.150. The beneficiary may release the trustee from liability to the beneficiary for past violations of AS 13.36.105 - 13.36.220.