Proposal by the seller to modify one or more clauses of the offer to purchase. The seller may want to change the sale price offered by the promising buyer (if it is lower than the one he requested), the date of the transfer of ownership, inclusions and exclusions, etc. The counter-offer renders the initial offer to purchase null and void. To follow up, the buyer will have to respond to the seller's counter-offer within a specific period. As part of the negotiation process, there may be several offers and counter-offers between the seller and the buyer.