There are two main issues to be dealt with in order to answer this question. Identify what is certified to be a valid offer and a valid acceptance. The second issue is knowing and analyzing the rules which determine the validity of withdrawal.
First and foremost, to have a valid contract, there must be valid offer, acceptance and consideration. A contract is described as a legally binding agreement between two parties. An offer is essentially the expression of willingness to be bound on certain and specific terms. Acceptance is the unqualified assent to all terms of the offer and the assent must be communicated to the offeror.
An offer must be first distinguished from a mere statement of price and invitation to treat. After distinguishing it, there must be acceptance. Therefore, communication between parties is imperative. An apt example for miscommunication would be the case of Felthouse v Bindley. The postal rule was developed due to the Adams v Lindsell case in 1818. Postal rule states that the moment a a letter of acceptance is posted, a contract is formed.
In any case, an offer can always be revoked and withdrawn as long it is before acceptance. An offer can be possibly revoked at any time before the offer is accepted as in Routledge v Grant. Hence, communication is as important in withdrawal of offer as it is in acceptance. Revocation of offers can occur in both bilateral and unilateral offers.
Bilateral offers are offers that in which both the parties has knowledge of one another e.g Byrne v Van Tien Hoven and Dickinson v Dodds. Withdrawal must be made before acceptance or else, the contract is formed. In circumstances whereby the withdrawal was known by the offeree after the acceptance has been made, the withdrawal is made null and the offer still