Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 60, § 84

If the collector has reasonable cause to believe that a tax title, held by a town under a sale or taking for non-payment of a tax, is invalid by reason of any error, omission or informality in the assessment, sale or taking, he may disclaim and release such title by an instrument under his hand and seal, duly recorded in the registry of deeds.  If the invalidity of a tax title so disclaimed and released or of a tax title released under section eighty-two or eighty-three was caused by an error, omission or informality in the assessment, the collector shall, upon the recording of such disclaimer and release or after obtaining from the holder of the deed a release of his interest or after causing a copy of the notice to be filed and recorded as provided in section eighty-three, forthwith notify the board by which the tax or assessment was laid, which shall forthwith reassess it as provided in section seventy-seven of chapter fifty-nine.  If such invalidity was caused by an error, omission or informality in the proceedings of the collector, he shall, after the recording of such disclaimer and release, or after obtaining such release or after filing or recording such copy, forthwith collect the unpaid tax or assessment in conformity to law.