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, by mistake, words are omitted or inserted, creating a greater,1 or less,2 estate than that agreed upon, reformation may be given. So where words creating a fee,3 such as "and their heirs forever,"4 are omitted; or where the phrase, "their bodily heirs," was used by mistake for "their heirs";5 or "successors" is used by mistake for "heirs"6 or an instrument whereby a means to reserve to himself a life estate, passing the fee to B, is by mistake so worded as to constitute a will;7 or a deed meant to pass an undivided interest in realty is by mistake so drawn as to pass the entire realty,8 reformation can be had. So reformation may be given where by mistake a condition subsequent has been omitted.9