Massachusetts General Laws
Article 10 - Liability of Trustees and Rights of Persons Dealing With Trustee
Section 1009 - Beneficiary's Consent, Release or Ratification

Section 1009. Beneficiary's consent, release or ratification
A trustee shall not be liable to a beneficiary for breach of trust if the beneficiary, while having capacity, in writing, consented to the conduct constituting the breach, released the trustee from liability for the breach or ratified the transaction constituting the breach, unless:
(1) the consent, release or ratification of the beneficiary was induced by improper conduct of the trustee; or
(2) at the time of the consent, release or ratification, the beneficiary did not know of the material facts relating to the breach.