commuted/commutation

The Racketeerを読んでいますが、今日の単語は8/28/2012に取り上げていました。 Once we’ve agreed, then I’ll give you the name of the killer. You grab him, investigate him, and when the grand jury indicts him for the murder, I will suddenly be transferred to another prison. Except I will not be serving any more time. I leave here as though I’m being transferred, but instead I go into your witness protection program. My sentence will be commuted, my record expunged, my name changed, and I’ll probably want some plastic surgery to alter my appearance.
"commute" の復習です。
・Oxford English Dictionary: Reduce (a judicial sentence, especially a sentence of death) to one less severe: the governor recently commuted the sentences of dozens of women convicted of killing their husbands
・Merriam-Webster's Online Dictionary: to change (a penalty) to another less severe: commute a death sentence to life in prison
上の引用文の後に名詞形の "commutation" も次のように出て来ました。
Rule 35 of the Federal Rules of Criminal Procedure provides the only mechanism for the commutation of a prison sentence. Its logic is brilliant and fits my situation perfectly. If an inmate can solve another crime, one that the Feds have an interest in, then the inmate’s sentence can be reduced.