Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 60, § 46

If it subsequently appears that, by reason of an error, omission or informality in the assessment or the sale, the purchaser has no claim upon the property sold, he may within six months after the date of the deed, offer by writing given to the collector to surrender and discharge his deed or to assign and transfer to the town all his right, title and interest in the premises, as the collector shall elect. Such offer shall contain a specific statement of the reason why the holder has no claim on the land sold, with the evidence on which he relies, and if such evidence consists of any public record or of facts shown therein, such offer shall contain a specific reference thereto. Upon such surrender and discharge or assignment and transfer, the town shall pay to the purchaser the amount which he paid, with interest at the rate of eight per cent per annum, which payment shall be in full for all damages for any defects in the proceedings or under the warranty in such deed. No town and no treasurer or collector thereof shall pay or be liable for any amount due under this section unless such statement is filed.

Upon such payment except in case an assignment and transfer is given to the town, the collector shall cause a surrender and discharge of the tax title deed to be recorded in the proper registry of deeds; and thereupon, if the error, omission or informality by reason of which it appears that the purchaser has no claim upon the property sold occurred in the assessment of the tax or assessment, the collector shall 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, and if it occurred in the proceedings of the collector, he shall forthwith proceed to collect the unpaid tax or assessment in conformity to law.