A more thorough explanation:

A counteroffer is a response to an offer made during contract negotiations. It is both a rejection of the original offer and a new offer that changes the terms of the original offer. When a counteroffer is made, the original offer is no longer valid and cannot be accepted.

For example, if a seller offers to sell a car for $10,000, and the buyer responds by offering to buy the car for $8,000, this is a counteroffer. The original offer of $10,000 is no longer valid, and the seller can either accept the new offer of $8,000 or make a counteroffer of their own.

Another example is if an employer offers a job to a candidate with a salary of $50,000 per year, and the candidate responds by asking for a salary of $60,000 per year. This is a counteroffer, and the original offer of $50,000 is no longer valid. The employer can either accept the new offer of $60,000 or make a counteroffer of their own.

These examples illustrate how a counteroffer works by showing how it changes the terms of the original offer and voids the original offer. In both cases, the parties must continue negotiating until they reach an agreement that is acceptable to both sides.