Can I cancel my offer to purchase based on the seller's disclosure stating two termite treatments. Also they changed the Insp. period from 15 to 10.

If changes were made to a contract after you signed the contract and you did not agree to these revisions by initialing the changes, then it would not appear to be a binding contract. Rather, the seller, by making the changes, has made a counteroffer that you, apparently, did not accept.  However, since there are usually two sides to a story and there may be additional facts that you have not stated, you should discuss the matter with a local attorney.  As a general rule, most purchasers of real property in Florida would be far better served by having a competent real estate attorney representing them from the contract-review stage through closing, rather than seeking counsel only after the problems have occurred.   The foregoing is specific to the law and procedure in Florida.  This response does not constitute legal advice as the facts presented are limited and unstated facts will likely impact your particular situation. This response is intended for general education only and does not create an attorney-client relationship. Please schedule a consultation with a local attorney for more specific and detailed answers to your legal issues.