If you have a SW flight booked and need to change it to the "Fully Refundable" fare, what portion is refundable? The new flight would be using the credit from changing the original flight - so if you had to cancel, would you only be able to get a refund of the additional $$ paid and have the rest available as credit for future use, or is there a way to get the full amount refunded? It seems that they wouldn't allow that since if you needed to cancel you could just pay the difference to change to refundable and then cancel and get all $$ back, but I thought I'd ask anyway.