Mass. Gen. Laws ch. 119, § 59

If a child has been placed in care of a probation officer, said officer, at any time before the final disposition of the case, may arrest such child without a warrant and take him before the court, or the court may issue a warrant for his arrest. When such child is before the court, it may make any disposition of the case which it might have made before said child was placed on probation, or may continue or extend the period of probation.