Why can I not accept an offer once there has been a bid?

I listed an item, starting at $1 no reserve. There was a bid for $1, and the auction is still running. Someone has since made a higher offer that I'd like to accept, but a message comes up saying I can't accept or counter an offer 'because the reserve has been met'. I don't understand why there is the option to make an offer, if offers can't be accepted. There is no way to contact the person who has made the offer.