Section 5A-401
If a guardian has been appointed in another state and a petition for the appointment of a guardian is not pending in the commonwealth, the guardian appointed in the other state, after giving notice to the appointing court of an intent to register, may register the guardianship order in the commonwealth by filing, as a foreign judgment, in an appropriate division of the probate and family court where an original proceeding could be filed, certified copies of the order and letters of office and of any bond.