Mass. Gen. Laws ch. 121B § 43A
If a person resides in a private dwelling unit or such other housing unit subject to regulations promulgated by the department not inconsistent with the standard required for dwelling units leased by a local housing authority under any federal or state rent subsidy program and if that unit does not meet reasonable standards of human habitation, provided that the tenant shall not have caused such conditions, and the authority has terminated the lease as to said substandard unit then the resident may vacate the substandard unit and may relocate in another unit. The housing authority shall assist the resident in locating another unit. The rental subsidy shall be withdrawn from the vacated substandard unit and shall be transferred to the unit in which the resident may relocate. If the alternate dwelling unit or said other housing unit is standard or if the owner of said unit agrees to make the unit standard and if the rental thereof is reasonable and acceptable to the housing authority in accordance with section forty-three, and if the owner of said unit is willing to enter into a leasing agreement with said authority, said authority shall expeditiously execute a lease for occupancy of said unit by said resident under the guidelines of the rent subsidy program affected.
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housing authority determines that a unit leased by it under a federal or state rent subsidy program is going to be withdrawn from such program by termination or expiration of the rental agreement with the owner of said unit, the occupant of said unit may relocate to another unit.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.
Mass. Gen. Laws ch. 121B, § 121B:43A