Acceptance is an expression signifying consent to the terms of an offer. In other words, to agree to the terms and conditions of an offer contract. The validity of an acceptance is governed by four principal rules. (1) it must take place while the offer is still in force, i.e. before it has lapsed or been revoked. (2) it must be on the same terms as the offer. An acceptance made subject to any variation is treated as a counteroffer. (3) it must be unconditional, thus an acceptance subject to contract is not a valid acceptance. (4) it must be communicated to the offeror. ….. ( Hyde Vs. Wrench (1840) 3 Beav 334; Carlill Vs. Carbolic Smoke Ball Co. (1983) 1 QB 256 )
As soon as the acceptance is posted or sent by telegram, the acceptance is complete against the proposer and the contract is concluded. A person posting a letter of acceptance is not answerable for casualties occurring at the post office- Consequently, the contract was complete and binding on the proposer immediately after the acceptance was posted and it was not revoked. It is rather the liability of the acceptor that would start only after the Acceptance comes to the knowledge of the proposer. ….. ( PLD 1984 Lahore 430 )
The communication of a counter offer does not amount to the acceptance of a proposal or an offer made by the other party. ….. ( Abdul Aziz Vs. The Rent Controller, PLD 1958 (Kar) 278 )
See, Sections 4, 7, 8 of the Contract Act, 1872; Sections 35, 112, of the Transfer of Property Act, 1882; Section 17, the Bill of Exchange Act, 1882.