Substantial compliance with donor-imposed formal requirement.

A powerholder's substantial compliance with a formal requirement of appointment imposed by the donor, including a requirement that the instrument exercising the power of appointment make reference or specific reference to the power, is sufficient if: (1) the powerholder knows of and intends to exercise the power; and (2) the powerholder's manner of attempted exercise of the power does not impair a material purpose of the donor in imposing the requirement.