Commutation (noun)

1. The act of changing or exchanging one thing for another.
2. A reduction or replacement of a punishment, especially a death sentence, with a less severe one.
3. The exchange of a regular payment for a lump sum.
4. The exchange of a transportation ticket for another, especially a less expensive one.

Origin:

Late middle english: from latin commutatio(n-), from the verb commutare "change".

Examples:

1. The commutation of his sentence caused controversy and criticism from victims' rights groups.
2. The employee was offered a commutation of his pension, exchanging regular payments for a lump sum.
3. The commutation of the ticket allowed her to travel on a different day at a lower cost.
4. She received a commutation of her sentence after 10 years in prison.
5. The commutation of the matrix was performed by swapping rows and columns.