If a petitioner becomes aware, after a court rules on a petition, that a condition of consent under § 5-3A-18(b) of this subtitle cannot be fulfilled, the petitioner promptly shall: file notice with the court; give notice to all of the other parties; if consent was received from a governmental unit or person who is not a party, give notice to that unit or person; and if the unit or person enters into a new consent, file the consent with the court; if the unit or person fails to enter into a new consent, ask the court to set aside the guardianship order; or if the unit or person cannot be located after exhaustion of the service requirements under § 5-3A-15 of this subtitle, ask the court to determine whether it is in the child’s best interests to continue the guardianship despite the inability to fulfill the condition.