a. If the court determines after hearing that continued placement serves the purposes of this act, it shall deny the petition. The court may, on its own motion, reduce the duration of the placement, change the agency or institution in which the child is placed, or direct the division to make such other arrangements for the child's care and welfare as the facts of the case may require.
b. If the court determines, after hearing, that continued placement does not serve the purposes of this act, the court shall discharge the child from the custody of the division or person given custody under section 34 hereof.