Unfortunately you cannot change/delete your bid amount once it is entered, you would need to contact the Seller via the Q&A facility (Ask the seller a question)  requesting that your bid be deleted and provide the reason for the request. The seller will be responsible for deleting your bid. If the bid is deleted you can re-bid on the item with the correct amount. Always ensure you take the necessary care when placing your bid as this can lead to disputes and problems after the close of the auction.