If the auction has ended, you cannot undo a bid
If the auction is still active, go to eBay’s Bid Retraction page
Sign in to your eBay account
Select the item you bid on
Choose the reason for retracting the bid
Submit the bid retraction request
If bid retraction is not available, contact the seller immediately
If you placed a Buy It Now bid, use the cancellation or order cancellation option if eligible
Review eBay’s bid retraction rules before submitting a request