Defendant's agreement to pay plaintiff a certain amount for furnishing a purchaser for land is not revoked by defendant's statement to plaintiff, after furnishing the name of one who afterwards became a purchaser, that he would pay no commission to any agent on a sale of the land unless a certain price was obtained, the plaintiff not having assented to the modification. Burd v. Webster, 128 Wis. 118, 107 N. W. 23; Odell v. Dozier, 104 Ga. 203, 30 S. E. 813; Levistone v. Landreux, 6 La. Ann. 26; Glade v. Eastern I11. Min. Co., 129 Mo. App. 443, 107 S. W. 1002; Cody v. Dempsey, 83 N. Y. S. 899, 86 App. Div. 335; Mottos v. Engle, 15 S. D. 330, 89 N. W. 651; Mark v. Elliott, 90 N. Y. S. 331; Blair v. Slosson, 27 Tex. Civ. App. 403, 66 S. W. 112; Bishop v. Averill, 17 Wash. 209, 49 P. 237, 50 P. 1024; Heimberger v. Rudd, 138 N. W. 374, 30 S. D. 289; Malloy v. Interstate Inv. Co., 114 P. 167, 62 Wash. 487; Arnold v. Schmeidler, 129 N. Y. Sup. 408, 144 App. Div. 420; U. S. Farm Loan Co. v. Darter, 183 P. 696, - Cal. App. - . See also Secs. 51, 485.