N - the buyer would have to retract, the seller cancels. But it's a moot point once the auction is over..Then there is a winner (or whiner, as the case may be)
and they'll either pay or they won't. Most bidders don't even know HOW to retract a bid, and even then it's only allowed under certain circumstances or the seller can report the person. However a seller can cancel any bids s/he wants, that's their call. But in JeffS' case, the auction was already over...nothing to be done.