Nevertheless, there are a number of rules apply in relation with the withdrawal of an offer. If an offeror withdraws from an offer but fail to communicate his withdrawal to the offeree, the offer is still considered as valid. Hence it is indeed vital for the offeror to bring the news of his withdrawal to the attention of the offeree. This can be seen in the case of Byrne v Van Tien Hoven whereby this case laid down the principle that an offer can only be withdrawn if it is communicated.
Besides, the revocation of an offer does not have to be communicated by the offeror to the offeree personally as it could also be done by a reliable third party such as the offeror’s lawyer or agent. This was illustrated in the case of Dickinson v Dodds whereby the defendant offered to sell his house to the plaintiff and the offer was opened until the 12th June. But the defendant sold his house on the 11th June to a third party and the plaintiff heard about it through a fourth man and later accepts the offer. However, the Court of Appeal held that the offer had been revoked by the communication of a fourth man.
In withdrawal of an offer, if an instantaneous method of communication such as fax, telax, or telephone was used to communicate it’s withdrawal, it will instantly take effect as shown in Entores v Miles .
On the other hand, in a unilateral contract, an offeror can revoke his offer by taking reasonable steps such as putting paper advertisement or through public announcement which must be done quickly. This is simply because if the offeree has commenced performance in regard to the offer then the offeror can revoke the offer any more as shown in Errington v Errington case. This case was also supported by dicta in Daulia v Millbank Nominees (1978).
Furthermore, when an offer is make via postal, it can also be revoked. However, it has got to be done before the offeree post an acceptance in reply to the offer. It is immaterial whether the offer is expressed to be open for acceptance for a given time or not. An offer can also be withdrawn if it was not properly addressed, stamped and posted.
Last but not least, an offer can also be withdrawn when the specified length of period has ended. And if the offeror has not mentioned how long the offer will remain valid, it will also lapse after a reasonable length of time depending on the subject-matter of the contract. For perishable goods such as food, a "reasonable time" would likely be a matter of days. The "reasonable time" would be longer where the subject matter of the contract is a building.
In conclusion, it is indeed true that offers may be withdrawn at any time up until acceptance, provided that the offeror followed the rules of a withdrawal.