Once an autobid is placed, it is not possible to cancel or reverse it. It is possible to increase or decrease this autobid. This can be done as following:
1) Place a new bid on the same lot and tick 'auto bid'.
2) The text ‘You are already the highest bidder. Check if the bid is correct. "Is displayed.
3) When confirming this new bid (which may also be lower), the car bid has been adjusted. The text "the maximum amount of your car bid has been adjusted" is visible.