To commute a sentence means to reduce or lessen a sentence imposed initially after a criminal conviction. Commutation is a form of clemency that reduces the punishment for a crime, usually in the form of a reduced prison term, but it can also reduce court-ordered fines. Commuting a sentence can be done for a wide variety of reasons, such as old age, good behavior, an illness, or other factors as the circumstances around the sentenced person change. A commuted sentence replaces the original, court-ordered sentence, and it can be granted by the President of the United States for federal crimes or by the governor for state-level offenses. Commutation is part of the pardoning power, so the person (or board) with the pardoning power usually also exercises the power to commute sentences. Commutation is different from a pardon in that a pardon is full forgiveness for the crime for which the defendant was convicted, while a commutation is simply shortening the sentence.