There is no provision in the contract that sales of policies and annuities occurring before the contract became effective or after its termination are covered by the terms of the contract. Importantly, FMS does not specifically relate the extrinsic evidence upon which it relies to the interpretation of any contractual terms relevant to the issue before us, namely, whether any restrictions on competition extend beyond termination of the 1990 contract. FMS simply alleges that the evidence creates a genuine issue as to whether the 1990 agreement not to compete continues after termination of the contract. We conclude FMS’s reliance on extrinsic evidence is in reality an inappropriate attempt to vary the terms of the agreement. See Bankers Trust Co. v. Woltz, 326 N.W.2d 274, 276 (Iowa 1982) (<HOLDING>). We think the district court did not err in
holding that court may not use extrinsic evidence unless contract language is ambiguous holding that a court may consider extrinsic evidence to determine whether a contract is ambiguous holding that extrinsic evidence of the parties course of conduct may be considered where the contract language is ambiguous holding that extrinsic evidence is permissible to interpret an ambiguous contract holding extrinsic evidence may be used only to interpret not alter a written contract