So i booked a flight for this summer, GSO-SFO-AVP-GSO, in October and did it because I beleived I had found what was a pretty good deal at $450 r/t. This has held true as a good deal and I am glad I booked it when I did, but now I need to make a change on the AVP-GSO leg to leave at a later time. However, the fare is at $650 meaning it would cost me about $200-$250 for the change and would cost my girlfriend the same. Anyone know any way to make the change without it costing me a ton? What is the financial penality if you miss a flight? Its not something I would want to do, but what if I "missed my flight?"