Settlement: Acceptance in Settling or Relinquishing a Claim or Right
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 2174
If a person wishes to settle a claim or right with someone, it will be valid only if the latter accepts. However, if he wishes to relinquish a claim or a right of his, the acceptance of the other party is not necessary.
-Ayatullah Sistani, Practical Laws of Islam, Settlement (Sulh)