exchange contracts

(law, England & Wales, Northern Ireland, idiomatic) To formally contract to purchase, sell or otherwise be party to a disposition of an estate in land; usually requiring the payment of a deposit by one of the parties.

(law, England & Wales, Northern Ireland, chiefly by legal practitioners) To create a conveyancing contract between negotiating parties by a process which is immediately followed by the exchange of signed counterparts of the contract between each party's legal representative.