Is there a way to cancel an auction in the auction house, or change the buyout price?

Solution 1:

Edit: Updated for 1.0.4

You can cancel any auction, so long as no bids have been made on it yet.

If you want to change the buyout price, you will need to cancel the auction (assuming no current bids), and re-list it with the new starting/buyout prices).

The ability to cancel auctions with no bids was added in patch 1.0.4. Prior to that, the following historical answer was valid:

You have 5 minutes from the start of the auction to cancel it. Once you are past that 5 minute mark, there is no way to end the auction early, short of someone purchasing the item via buyout.

You cannot change the minimum bid or buyout price once the auction is started.

Your only options are to wait and see if someone buys it, or possibly give someone else (that you trust!) the money for the buyout, have them buy it, give it back to you, and put it back on the AH at a new price. Keep in mind that you will wind up losing money this way to the AH fees, however.

Solution 2:

Yes there is actually a way to cancel auction early. What you need to do is have the auctions page open showing the current auctions you have posted up. Then you need to go to your system tray in the bottom right and double click the time. From here go to the calendar and set the day back roughly 2 days. Once you apply this change you should see your auctions allow you to cancel them right away.

Solution 3:

As of the 1.04 patch on 8/21/2012, it is possible to cancel an auction at any time if no bids have been placed on it. Once a bid is placed, the auction cannot be cancelled and you have to wait for it to end or for the buyout price to be paid.