Commutation
The Cyclopedic Law Dictionary · Walter A. Shumaker and George Foster Longsdorf; ed. James C. Cahill · 1922
The Cyclopedic Law Dictionary
The change of a punishment to which a person has been condemned into a less severe one. This can be granted only by the executive authority in which the pardoning power resides. Not a conditional pardon, but "the substitution of one punishment known to the law for another and different punishment, also known to the law."
1 Nev. 321.
The substitution of a punishment of a lower degree for one of a higher degree.
257 111. 566.