I agree with Erin, she either wants a certain amount or has found someone who has offered her an amount so she needs to change it to buy it now so they can buy it. Mind you, you're not supposed to do this either! If you list as auction, you're supposed to let it run it's course, that's just how it is. I don't think she's going to come to an agreement... to be honest, I would skip that and lodge a complaint and dispute.