Русско-англо-русский юридический словарь

Supplemental agreements are legally binding documents that are used to modify contracts that are already in force. This type of document is sometimes used as a means of allowing the existing agreement to remain in place with the same ending date, while adding or removing some provisions or terms to the working relationship. A supplemental agreement is often an ideal solution when there is no desire to renegotiate an entirely new contract to take the place of the current agreement. (WiseGEEK)

Settlement Agreements. To put it simply, this is a legally binding document used by both parties to resolve the ongoing dispute. (Wilson Browne Solicitors)