I booked our airfare this morning and when I checked them just now, our return flight dropped $10 a person. Not super huge but $40 could work out if we get a good DING. How do I go about getting the new price? Do I have to cancel and rebook? I booked both ways at the same time if that makes a difference. Also, what if I change them now, for my measly $40 and then tomorrow or next week, they go down again, can I keep rebooking as many times as necessary?