This section is from the book "The Law Of Contracts", by William Herbert Page. Also available from Amazon: Commercial Contracts: A Practical Guide to Deals, Contracts, Agreements and Promises.
Provision is frequently made in contracts for subsequent modification thereof. Modifications which are made pursuant to such provisions are ordinarily regarded as not intended to affect the existence and validity of the original contract, but merely as subsidiary contracts entered into for the performance thereof.1 The presumption against a total discharge of the original contract by mutual consent is stronger than it would be in cases where no such provision in the original contract existed.2 If a building contract contains a provision to the effect that the owner may make alterations and additions without affecting its validity, and that an allowance shall be made for the value thereof, a subsequent agreement changing the plans and specifications and eliminating certain parts of the original contract, does not operate as an abandonment of the original contract and a substitution of the new contract therefor.3 Such a provision, however, does not authorize the owner to make a radical change in the subject-matter of the contract.4 A similar provision in a contract for the construction of a dam to be built of masonry, does not authorize the owner to change such contract to one for the construction of a dam to be made of earth with a core of masonry,5 at least if the contract provides that the contractor is to take in payment bonds secured by a mortgage upon such completed structure.6
6 Goebel v. Linn, 47 Mich. 489, 41 Am. Rep. 723, 11 N. W. 284; Blodgett v. Foster, 120 Mich. 392, 75) X. W. 625; Agel v. F. R. Patch Mfg. Co., 77 Vt. 13, 58 Atl. 792.
See ft 589.
7 Frankfurt-Barnett Co. v. William Prym Co., 237 Fed. 21, L. R. A. 1918A, 602; Alabama Oil & Pipe Line Co. v. Sun Co., 99 Tex. 606, 92 S. W. 253 [judgment reversed (Tex. Civ. App.), 90 S. W. 202].
8 Sherman v. Buffinton, 228 Mass. 139, 117 X. E. 33; Murphy v. Dalton, 139 Mich. 79, 102 N. W. 277.
9 Frankfurt-Barnett Co. v. William Prym Co., 237 Fed. 21, L. R. A. 1918A, 602.
10 Murphy v. Dalton, 139 Mich. 79, 102 N. W. 277.
11 Sherman v. Buffinton, 228 Mass. 139, 117 N. E. 33.
12 Sherman v. Buffinton. 228 Mass. 139, 117 N. E. 33.
1Gray v. Jones, 47 Or. 40, 81 Pac. 813.
2Gray v. Jones, 47 Or. 40, 81 Pac 813.
A contract which provides that it is to be performed under the supervision and inspection,7 or to the satisfaction,8 of the engineer or architect of the owner, does not authorize such engineer or architect to modify such contract so as to require the contractor to furnish more expensive work at the price fixed by the contract,9 or to require a change in the method of construction.10 A contract in writing, for grading a street, in which the employer reserves the right to decide how much work is to be done, and to stop the work at any time, is not abrogated by a subsequent request by the employer that the contractor should increase his working force to such number of men as could complete the grading within a certain time. The employer may subsequently exercise his right to stop the work.11