http://offer.ebay.ca/ws/eBayISAPI.dll?RetractBidShow
The reasons for a Retraction are limited. Your Retractions show on your Feedback page.
You can also request the seller to cancel your bid. He is not required to agree, but most will, to avoid the hassle of chasing a non-paying bidder. He will probably put you on his Blocked Bidder List.
