What is the difference between a contract and an offer? Same difference right? Not so much.
An offer is not legally binding where a contract is. An offer becomes a contract once all signatures have been collected.
What happens if someone makes a change during negotiations? During negotiations if one party makes changes to the terms and signs the document that creates a counteroffer. As long as all parties agree on those changes and initial them the counteroffer becomes a contract.
And remember – just because you make an offer does not mean that the seller has to respond, counter or accept it!