A buyer has emailed and aske dif they can buy my item now, even though I haven't set a 'buy now ' price. I have an active bid
To accommodate this chancer, you'd first have to cancel all existing bids - bear in mind that those bidders won't return.
Then you'd have to relist at the agreed price (more costs) and then you'd have to hope that the person actually buys - most don't.
Up to you.
I bid, I win, I pay - you deliver