If the auction is still active then ask the seller to remove your bid as a change of mind is not an option to retract a bid.
If the auction has ended and you have won it then you need to contact the seller and ask if they will send an agreement to mutually cancel that you need to agree to once you get it to release you from the purchase.
If you have won it then the seller is within their rights to open a non payer dispute and issue a non payer strike for not paying.
PLEASE never bid if you do not want the item as it is not fair to the sellers.
