Mass. Gen. Laws ch. 151A § 71
The commissioner may reconsider a determination whenever he finds that (1) an error has occurred in connection therewith; or (2) wages of the claimant pertinent to such determination but not considered in connection therewith have been newly discovered; or (3) benefits have been allowed or denied or the amount of benefits fixed on the basis of misrepresentation of fact; provided, however, that with respect to (1) and (2) no such redetermination shall be made after one year from the date of the original determination; and provided, further, that with respect to (3) no such redetermination shall be made after four years from the date of the original determination; and provided, further, that the time limitations specified above shall not apply with respect to an award of back pay received by an individual for any week in which unemployment benefits were paid to such individual. If the commissioner reconsiders a determination under this section, parties entitled to notice of the original determination shall be afforded an opportunity for an interview before the commissioner or his authorized representative for the purpose of presenting evidence or refuting opposing positions before such a determination can be made.
Notice of any such redetermination shall be promptly given to the parties entitled to notice of the original determination, in the manner prescribed in this chapter with respect to notice of an original determination. If the amount of benefits is increased upon such redetermination an appeal therefrom solely with respect to the matters involved in such increase may be filed in the manner and subject to the limitations provided in sections thirty-nine to forty-two, inclusive. If the amount of benefits is decreased upon such redetermination, the matters involved in such decrease shall be subject to review in connection with an appeal by the claimant thereon or from any determination upon a subsequent claim for benefits which may be affected in amount or duration by such redetermination. Subject to the same limitations and for the same reasons, the commissioner may reconsider the determination in any case in which a decision has been rendered by the board of review or a court, and may apply to said board or such court which rendered such decision to revoke or modify such decision and the board of review or court may affirm, modify or revoke such decision.
In the event that an appeal involving an original determination is pending as of the date a redetermination thereof is issued, such appeal, unless withdrawn, shall be treated as an appeal from such redetermination.
The commissioner may reconsider a decision issued pursuant to section twelve or subsection (b) of section thirty-nine for which no application for review pursuant to section twelve or section forty was filed when in his judgment it appears that because of newly discovered evidence or for any other reasonable cause the commissioner should reconsider the decision. The commissioner shall not reconsider any decision after one year from the date of the original decision. Any party who files a request for reconsideration with the commissioner shall mail a copy of said request to every other party to the original hearing.
If the commissioner reconsiders a decision under this section, the commissioner shall revoke the original decision and reopen the original hearing, giving notice to all parties to the original hearing. The commissioner or the commissioner's representative shall conduct the hearing in accordance with the procedures prescribed by section twelve or subsection (b) of section thirty-nine, whichever is applicable. The commissioner or the commissioner's representative shall give notice of such decision, together with the findings and reasons thereof, to the parties. Any party aggrieved by the decision may file an application for review as provided by section twelve or section forty, whichever is applicable. Benefits shall be paid promptly or denied in accordance with such decision. Unless action is taken under said section twelve or said section forty, the decision shall be final on all questions of fact and law.
Subject to the same limitations and for the same reasons, the commissioner may reconsider a decision in any case in which the board of review or court has rendered a decision and may apply to said board or court to revoke or modify such decision and the board or court may affirm, modify or revoke such decision.
The decision of the commissioner not to reconsider a decision shall be final and not subject to appeal under any provision of this chapter.
Mass. Gen. Laws ch. 151A, § 71