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 case the said A..B. shall fail to perform his covenant hereinbefore set forth, whereby he agrees to [insert substance of specific covenant], the said C. D. may, at his election, declare such contract as terminated and discharged. Said election shall be made by a written notice to that effect, served on A. B. by the said C. D. or by someone authorized by said C. D. to serve such notice. In case said C. D. shall elect to treat such breach on the part of A. B. as a discharge of such contract, said C. D. may nevertheless maintain an action to recover damages arising out of said breach.