Under which pardoning power of the President, one form of punishment is substituted by a lighter form?

Article 72 of the Constitution empowers the President to grant five types of pardon to persons who have been tried and convicted of any offence : pardon, commutation, remission, respite and reprieve. Commutation denotes the substitution of one form of punishment for a lighter form. For example, a death sentence may be commuted to rigorous imprisonment, which in turn may be commuted to a simple imprisonment.