If an infant or incompetent person has a representative, including a general guardian, committee, conservator, or similar fiduciary, the representative may file a voluntary petition on behalf of the infant or incompetent person. An infant or incompetent person who does not have a duly appointed representative may file a voluntary petition by next friend or guardian ad litem. The court shall appoint a guardian ad litem for an infant or incompetent person who is a debtor and is not otherwise represented or shall make any other order to protect the infant or incompetent debtor.