Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 92, § 84

The department may, with the concurrence of the park commissioners, if any, of the town within the urban parks district where the property is situated, by deed recorded in the county where the land lies, accompanied by plan or survey, abandon any easement or other right in land less than the fee taken by the department by right of eminent domain for reservation or boulevard purposes, and said abandonment shall revest title thereof, as if never taken, in the persons, their heirs and assigns, in whom vested at the time of the taking.