An attorney may bind a client, at any stage of an action or proceeding, by agreement made in open court or in the presence of the court administrator, and entered in the minutes by such court administrator, or made in writing and signed by such attorney. During any proceeding or action the attorney may receive money claimed therein by a client, and within six years after judgment, upon payment thereof, may discharge the claim or acknowledge satisfaction of the judgment; but all such authority shall cease upon the substitution of another attorney.