commutation

(noun) the travel of a commuter. Synonyms: commuting.

(noun) a warrant substituting a lesser punishment for a greater one.

(noun) (law) the reduction in severity of a punishment imposed by law. Synonyms: re-sentencing.

(noun) the act of putting one thing or person in the place of another: "he sent Smith in for Jones but the substitution came too late to help". Synonyms: substitution, exchange.