Ala. Code § 19-3A-605

A fiduciary may at any time obtain the written consent of all of the current income beneficiaries and presumptive remainder beneficiaries of a trust or decedent’s estate as to the fiduciary’s exercise of any discretion granted under this chapter, including the application of the chapter to pre-existing trusts or decedent’s estates, and such written consent shall conclusively bind all persons who may have any interest in the affected trust or decedent’s estate, including all contingent remainder beneficiaries and potential appointees of the affected trust or decedent’s estate.