(a) The court shall retain jurisdiction over a guardianship action under this part for the sole purpose of entering an order following the filing of a petition to modify, vacate, or revoke the guardianship and
appoint a new guardian.
(b) The superior courts shall have concurrent jurisdiction for enforcement or modification of any child support or visitation order entered pursuant to Code Section 15-11-240.
(c) The guardianship shall be modified, vacated, or revoked based
upon a finding, by clear and convincing evidence, that there has been a material change in the circumstances of the child who was adjudicated as a dependent child or the guardian and that such modification, vacation, or revocation of the guardianship order and the appointment of a new guardian is in the best interests of the child. Appointment of a new guardian shall be subject to the provisions of Code Sections 15-11-240 and 15-11-241.