The acts which the offeree must have performed in reliance on the offer may consist in making preparations for production, buying or hiring of materials or equipment, incurring expenses etc., provided that such acts could have been regarded as normal in the trade concerned, or should otherwise have been foreseen by, or known to, the offeror. A, an antique dealer, asks B to restore ten paintings on condition that the work is completed within three months and that the price does not exceed a specific amount. A agrees and B, relying on A's offer, begins work immediately. A may not revoke the offer during those five days. A seeks an offer from B for incorporation in a bid on a project to be assigned within a stated time.
B submits an offer on which A relies when calculating the price of the bid.
Before the expiry of the date, but after A has made the bid, B informs A that it is no longer willing to stand by its offer. B's offer is irrevocable until the stated date since in making its bid A relied on B's offer.