Explanation:

- Waiver: This is when a party voluntarily relinquishes a known right or claim. For example, if a lender decides not to enforce a contract clause.

- Remission: Accepting a lesser sum than what was originally agreed upon in a contract to settle the whole debt. This involves forgiving part of the debt.

- Alteration: This involves changing the terms of a contract, either partially or entirely, with the consent of both parties.

- Rescission: The cancellation or annulment of a contract, with the intent of returning the parties to the position they were in before the contract.

Correct Answer: Remission