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.
In some jurisdictions, however, it is held that a mistake in expression can not be corrected by the action of one party alone, and that such a correction is an alteration, avoiding the contract if otherwise material,1 though ordinarily not fraudulent. If a note is given to renew a former note, but three of the makers were not parties to the original note, a change in the date of such note is a material alteration as to such new parties, even if it was made so as to conform to the real intention of all the parties to the original note.2 An alteration in a note, which increases the rate of interest, is held to avoid the note, although such alteration was made innocently in order to make the note express the real agreement into which the parties had entered.3
 
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