This morning I encounted a rare occurance with the Diablo 3 auction house.
I had a bid on an item where I was winning with a few hours left to go.
During the course of my game playing I found an item that was better than what I was wearing AND better than the item that I had a bid on. I went to the auction house interface and could not find a way to cancel the winning bid I had on the item. Luckily for me, someone else bid and won the item before the auction ended so I recovered my gold.
The question is, am I able to/can I cancel my bid an item?