Explanation:

Pardon: It annuls both the sentence and the conviction and absolves the offender from all punishment and disqualifications
Commutation: It merely substitutes one form of punishment for another of a lighter character. For example death sentence can be commuted to rigorous imprisonment, rigorous imprisonment to simple imprisonment and simple imprisonment to fine.
Remission: It reduces the amount of sentence without changing its character. For example a sentence of imprisonment for one year may be remitted to six months.
Respite: It means awarding a lesser sentence instead of the penalty prescribed, in view of some special fact, e.g., the pregnancy of a woman offender.
Reprieve: It means stay of execution of a sentence, e.g., pending a proceeding for pardon or commutation.