If custody of a child has been vested by the court in an individual, institution, or agency, other than the Department of Corrections, a parent whose parental rights have not been terminated, or a former guardian or custodian of the child may petition the court for restoration of custody or other modification or termination of the prior custodial order or decree on the ground that a change of circumstances has occurred which requires the modification or termination in the best interests of the child, the public and the state.
SDCL 26-7A-109