A broker employed to procure a person ready, able and willing to contract for an exchange of real estate on terms satisfactory to both parties to the exchange, is not entitled to a commission unless he produces a person willing to exchange on the terms named by the owner. Bucksdorf v. Bender, 141 N. Y. Supp. 515, 80 Misc. Rep. 498; Davis v. Gottschalk, 141 N. Y. Sup. 517, 80 Misc. Rep. 530.