Massachusetts General Laws Part III. Courts, Judicial Officers and Proceedings in Civil Cases (Ch. 211-262) Ch. 240, § 27

Any person having, in a representative or fiduciary capacity or otherwise, a power or authority created by any written instrument to sell, convey, mortgage or otherwise transfer any interest in real estate may file a petition in the land court setting forth the act or acts which he proposes to do by virtue of such power or authority, and praying that his power or authority under such written instrument to do such act or acts may be established.