There shall be one arbitrator, and such arbitrator shall be chosen by mutual agreement of the parties in accordance with AAA rules. (cosmolex.com)
Often a discount, if any, is arrived at by mutual agreement between the parties. (remonline.com)
It is typical for family law mediation sessions to begin with the parties stating which issues they have already resolved by mutual agreement. (divorceandfamilymediationservices.com)