Intercessor

[L., a surety: cf. F. intercesseur.]

1. One who goes between, or intercedes; a mediator. (a) One who interposes between parties at variance, with a view to reconcile them. (b) One who pleads in behalf of another. Milton.

2. (Eccl.) A bishop, who, during a vacancy of the see, administers the bishopric till a successor is installed.

noun

Someone who acts as an intermediate agent in a transaction or helps to resolve differences: broker, go-between, interceder, intermediary, intermediate, intermediator, mediator, middleman. See means.