(a) The court retains jurisdiction over the case and may at any time stay execution, modify, set aside, revoke, or enlarge a judgment or order, or grant a new hearing, in the exercise of its power of protection over the child and for the child's best interest, for a period of time not to exceed two years or in any event extend past the day the child reaches 19 years of age, unless sooner discharged by the court, except that the department may apply for and the court may grant an additional one-year period of custody or supervision past 19 years of age and additional one-year periods of custody that do not extend beyond the person's 21st birthday if continued custody or supervision is in the best interests of the person and the person consents to it. An application for any of these purposes may be made by the parent, guardian, or custodian acting in behalf of the child, or the court may, on its own motion, and after reasonable notice to interested parties and the appropriate department, take action that it considers appropriate.

(b) If the court determines at a hearing authorized by (a) of this section that the department has complied with the requirements for release of a child under AS 47.14.100(q) and that it is in the best interests of the child to be released to the child's own custody, or to the care or custody of the child's parent, guardian, or custodian, it shall enter an order to that effect and the child is discharged from the control of the department.

(c) If a child is adjudicated a child in need of aid before the child's 18th birthday, the court may retain jurisdiction over the child after the child's 18th birthday for the purpose of supervising the child, but the court's jurisdiction over the minor under this chapter never extends beyond the child's 19th birthday, except that the department may apply for and the court may grant an additional one-year period of custody or supervision past 19 years of age and additional one-year periods of custody that do not extend beyond the person's 21st birthday if continued custody or supervision is in the best interests of the person and the person consents to it. The department may retain jurisdiction over a child if the child has been placed in the custody or under the supervision of the department before the child's 18th birthday, except that the department may apply for and the court may grant an additional one-year period of custody or supervision past 19 years of age and additional one-year periods of custody that do not extend beyond the person's 21st birthday if continued custody or supervision is in the best interests of the person and the person consents to it.