(a) Unless the trust's governing instrument expressly provides that the governing instrument may not be modified under this section, under a nonjudicial settlement agreement under § 3338 of this title or similar provision of law, or under a modification agreement, an irrevocable trust may be modified by the addition of a new provision or the modification of any existing provision—so long as such provision could have been included in the governing instrument of a trust were such trust created upon the date of the modification—by written consent or written nonobjection of all of the trust's trustors, all then serving fiduciaries and all beneficiaries having an interest in the trust, regardless of whether the modification may violate a material purpose of the trust; provided, however, that unless the trustor, or a person acting on behalf of the trustor, confirms in writing that the transfer in trust is an incomplete gift for federal gift tax purposes, neither a trustor nor, on behalf of a trustor, a guardian or an agent under a power of attorney, may represent and bind any beneficiary (other than the trustor) with respect to the modification, notwithstanding any provision in the governing instrument, or applicable law, that provides that the trustor may represent or bind 1 or more beneficiaries. A trustor's power to provide a written consent or written nonobjection to a trust's modification may be exercised:
(1) By an agent under a power of attorney only to the extent expressly authorized by the power of attorney or the terms of the trust's governing instrument; or
(2) If an agent under a power of attorney is not so authorized, by the guardian of the trustor's property (or similar court-appointed representative) with the approval of the court supervising the guardian (or similar representative).
(b) No fiduciary shall have a duty to consent to any proposed modification nor, absent wilful misconduct, have any liability to any person having an interest in the trust for failure to consent to any proposed modification.
(c) Any interested person, including the trustor, may bring a proceeding in the Court of Chancery to interpret, apply, enforce, or determine the validity of a modification adopted under this section, including but not limited to determining whether the representation as provided in § 3547 of this title was adequate; provided, however, that any such person may waive the right to contest the modification.
(d) This section shall apply to any trust administered under the laws of this State.