(a) If the settlor of a trust that is described under Subsection (a) of Section 112.055 of this Act is living and competent and consents, the trustee may, without judicial proceedings, amend the trust to expressly include or exclude the provisions required by Subsection (a) of Section 112.055 of this Act.
(b) The amendment must be in writing, and it is effective when a duplicate original is filed with the attorney general's office.