Commutation

A passing from one state to another; change; alteration; mutation.

The act of giving one thing for another; barter; exchange.

The change of a penalty or punishment by the pardoning power of the State; as, the commutation of a sentence of death to banishment or imprisonment.

A substitution, as of a less thing for a greater, esp. a substitution of one form of payment for another, or one payment for many, or a specific sum of money for conditional payments or allowances; as, commutation of tithes; commutation of fares; commutation of copyright; commutation of rations.

(law) the reduction in severity of a punishment imposed by law

a warrant substituting a lesser punishment for a greater one