Mass. Gen. Laws ch. 121B § 43A

Whenever a local housing authority determines that a unit leased by it under a federal or state rent subsidy program is going to be withdrawn from such program by termination or expiration of the rental agreement with the owner of said unit, the occupant of said unit may relocate to another unit. Such unit shall be leased by the Authority, provided that it meets all the requirements of the subsidy program under which the original unit was leased.