A Counter Proposal is a legal document generated by the Seller to provide to the Buyer for a contract received. A Counter Proposal should address only the terms and conditions being proposed that differ from the original contract. Everything in the original contract would remain the same with the exception of any new proposed terms and conditions. The Buyer now has the option to accept the new terms and conditions or not. A Counter Proposal accepted by the Buyer carries the same validity as the initial contract in terms of honoring the Counter Proposal by both parties.
Often times, you may have a Counter Proposal to a Counter Proposal which can become confusing to everyone involved if too many Counter Proposals are generated. It is best sometimes to just generate a new contract when all the terms and conditions have been agreed upon rather than going back and forth with numerous Counter Proposals.