It is important to probably talk to an attorney about the different analysis that needs to be looked at. There is a different analysis if one parent is the only legal parent; such as if this has occurred where the parties are not married and have not been any proceedings to determine paternity or custody rights versus if one parent has sole physical custody. 

There is an Order allowing the other parents that are divorced; or it has been determined by the court to have legal parenting rights versus if both parents have shared physical custody versus if there is not a strict custody determination in a prior agreement.  There are different standards for different types of custody orders that are important to go over with an attorney prior to considering moving out of Massachusetts in terms of the process if any, that the parent needs to take.