Discharge of Contract: When is it Effective?

Let's talk about the effect of discharge on a contract. In the case of Meston v. IBP Ltd ([1936] All ER 241), the court held that where a party has entered into a contract with one person and then makes an agreement with another person for discharge of that contract, the earlier contract is not discharged until the subsequent contract is accepted by the other party.

Now, let's consider two possible scenarios in relation to this. Scenario 1: A makes a contract with B for the sale of a property. Later, A and C enter into an agreement for the discharge of the contract between A and B. C accepts the agreement. Now, when does the contract between A and B get discharged? Scenario 2: Same as in Scenario 1, but C does not accept the agreement for discharge, but instead, returns it to A with the comment "I'll think about it".