If the offender has not yet undergone the punishment, or is undergoing the punishment, and the punishment determined by the judgment is heavier than that provided by the law afterwards, when it appears to the Court from the file of the case, or when the offender, the legal representative or guardian of such person, or the Public Prosecutor makes a request, the Court shall re-determine the punishment according to the law as provided afterwards. In re-determining the punishment by the Court, if it appears that the offender has undergone a part of the punishment, the Court, when having regard to the punishment as provided by the law afterwards, may, if it thinks fit, determine less punishment than the minimum punishment as provided by the law afterwards, if any, or if it is of opinion that the punishment already undergone by the offender is sufficient, the Court may release the offender;