The term 'act as a go-between' can be summarized by two crossword solutions: MEDIATE (7 letters) and LIAISE (6 letters). Mediation is a process in which a third party helps two or more parties to come to an agreement. This third party, known as the mediator, does not take sides or make decisions, but instead facilitates communication between the parties to help them reach a mutually beneficial outcome. Liaising is a similar process, but it involves a person who acts as a link between two or more parties. The liaison helps to coordinate activities and ensure that all parties are kept informed of progress.