A child who is 16 years old or older and who is subject to a custody order or decree may file a petition to change custody. A petitioner under this section may file the proceeding in the petitioner’s own name and need not proceed by guardian or next friend. Notwithstanding any other provision of this article, if a petitioner under this section petitions a court to amend a custody order or decree, the court: shall hold a hearing; and may amend the order or decree and place the child in the custody of the parent designated by the child.