You can normally withdraw your offer anytime until the sellers accept it in writing. Even if you give the sellers two days, for example, to accept and only one day has passed and they are still thinking about it, you can withdraw your offer. But once they sign, you're on the hook.

The legal complexities of contracts are quite arcane, as any attorney will tell you. And this is a good reason for consulting one when you have a problem with contracts. Having said that however, it must also be said that most agents understand that the general rule has always been that any offer, until accepted, can be withdrawn. The sticky part comes about in determining when the offer has been accepted and when it has been withdrawn.

Generally speaking, the offer has been accepted when the sellers sign (not just orally say they've accepted, but physically sign the agreement) an offer you have made, without any change to it whatever, and their acceptance has been conveyed to you. In other words, theoretically, the sellers could sign. But before they or their agent is able to tell you that they've signed, you could call up and shout out, "I withdraw my offer!" 

Is your offer withdrawn or is it too late? Can the sellers hold you to the deal, which you now may not want? Who said what first? This is a quagmire that might take several attorneys and a court to sort out.

In the real world, however, most of the times you won't want to withdraw your offer. (Unless, of course, in the meantime you've found a better house at a fraction of the price.) Also the sellers won't accept so quickly. Usually there's a period of extended negotiations, and you'll have many opportunities to withdraw. Just remember the following general rules:

- Unless the sellers sign your offer exactly as made with­out changing anything, you're not on the hook.

- If you make any changes to a counter from the sellers, you are now making a new offer, which they can accept or reject.

- You should always put a time limit on any offers or counters you make.

- You can withdraw an offer you make up until the sell­ers sign their acceptance, without making any changes of any kind, and their acceptance has been conveyed to you.

Knowing these rules is important because otherwise an unscrupulous seller or agent might try to bully you into accepting something that you definitely don't want and aren't required to accept.