Yes, providing there are no bids and more than 12 hours you can revise a listing.
You will need to add a Buy it now price which will need to be more than 30% of auction start price.
Then tick the box to have best offer.
Or you may want to end this listing and relist as Buy it now only with best offer.
That way you can have Buy it now as any price you want, not just 30% above an auction.
