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.
If the parties purposely omitted a part of their oral agreement from their written contract, no mistake exists except possibly in their belief that they can prove the oral contract and enforce it as well as the written one. In cases of this sort equity does not grant reformation.1 If the written contract is complete upon its face and the parties understand the language used in such contract and its legal effect, reformation can not be granted on the ground that an oral term of such contract which was omitted intentionally was not performed.2 Reformation can not be had for the purpose of correcting the nature of the estate conveyed;3 or for the purpose of inserting reservations,4 or exceptions to covenants,5 or covenants which have been intentionally omitted;6 or for the purpose of reforming receipts,7 since no mistake can be shown to exist and the effect of reformation will be to enforce oral provisions in violation of the parol evidence rule. Reformation is refused where a party to a deed discovers the mistake after execution but before delivery, but the deed is, nevertheless, delivered in the form in which it was originally drawn.8 Elementary as this proposition may seem in view of the so-called parol evidence rule,9 there is some authority for allowing an oral term of a contract agreed upon before the rest of the contract was reduced to writing and executed, to be added thereto by reformation.10 If the parties to a written contract have intentionally inserted terms therein in reliance upon an oral agreement that such terms shall not be enforced, the only mistake which exists is possibly the mistaken belief of the parties that such oral agreement can be enforced against the express terms of the written contract. Accordingly, in many jurisdictions equity will not grant reformation so as to eliminate from the written contract such term which has been inserted intentionally. In some jurisdictions, however, it is held that equity will enforce the real agreement of the parties and that it will eliminate from the contract the term which the parties agreed not to enforce.11 In jurisdictions in which this result is reached there is practically nothing left of the parol evidence rule in equity. A consistent application of this principle would require a court of equity to enforce the oral agreement of the parties without reference to the written contract, except in so far as it might impose a higher degree of proof upon the party who is seeking to reform the written contract. It would not be necessary to show mistake of any sort in order to obtain reformation. A written contract can not be reformed by adding a provision agreed upon by the parties orally after the written contract was made.12
26McIntrye v. Casey, - Mo. - , 182 8. W. 966.
27 Schlossor v. Nicholson, 184 Ind. 283, 111 N. E. 13.
28 Schlosser v. Nicholson, 1S4 Ind. 283, 111 N. E. 13.
29Andrus v. Blazzard, 23 Utah 233.
54 L. R. A. 354, 63 Pac. 888.
30 Wilson v. Watkins, 48 S. Car. 341. 26 S. E. 663.
1 Alabama. Ware v. Cowles, 24 Ala. 446. 60 Am. Dec. 482; Holland Blow Stave Co. v. Barclay, 193 Ala. 200, 69 So. 118.
Connecticut. Dunham v. New Britain,
55 Conn. 378, 11 Atl 354.
Kentucky. Pickrell & Craig Co. v. Castleman-Blakemore Co., 174 Ky. 1, 191 S. W. 680.
Maryland. White v. Shaffer, 130 Md. 351, 99 Atl. 66.
Massachusetts. Dwight v. Pomeroy, 17 Mass. 303, 9 Am. Dec. 148.
Michigan. Martin v. Hamlin, 18 Mich. 354, 100 Am. Dec. 181; Wood v. Standard Drug Store, 192 Mich. 453, 158 N. W. 844.
Missouri. Begal Realty & Investment Co. v. Gallagher, - Mo. - , 188 S. W. 151.
New Jersey. Seitz Brewing Co. v. Ayres, 60 N. J. Eq. 190, 46 Atl. 535.
Virginia. Meade v. Ry., 89 Va. 296, 15 S. E. 497.
Washington. Weinhard v. Summer-ville, 46 Wash. 127, 13 L. R. A. (N.S.) 1089, 89 Pac. 490.
Wisconsin. Braun v. Rendering Co., 92 Wis. 245, 66 N. W. 196; In re Pul-len's Will, 166 Wis. 254, 165 N. W. 25.
"It was a mere simultaneous parol agreement which can not be resorted to to vary or control the written contract." Braun v. Rendering Co., 92 Wis. 245, 249; 66 N. W. 196.
2Pickrell & Craig Co. v. Castleman-Blakemore Co., 174 Ky. 1, 191 S. W. 680.
3 Regal Realty & Investment Co. v. Gallagher, - Mo. - , 188 S. W. 151.
4 Holland Blow Stave Co. v. Barclay, 193 Ala. 200, 69 So. 118.
5 Weinhard v. Summerville, 46 Wash. 127, 13 L. R. A. (N.S.) 1089, 89 Pac. 490.
6 Wood v. Standard Drug Store, 192 Mich. 453, 158 N. W. 844.
7 In re Pullen's Will, 166 Wis. 254, 165 N. W. 25.
8McMillon v. Flagstaff, 18 Ariz. 536, 164 Pac. 318; White v. Shaffer, 130 Md. 351, 99 Atl. 66.
9 See oh. LXIX.
10Quinn v. Roath, 37 Conn. 16; Coger v. McGee, 5 Ky. (2 Bibb.) 321, 5 Am. Dec. 610; Taylor v. Oilman, 25 Vt. 411.