Originally Posted by
BearX220
Absolutely wrong. If that were generally true it would destroy fundamental airline pricing structure -- you have purchased a ticket from BTV to Russia, not JFK to Russia, and one is not as good as the other. You either have to go bacxk to BTV to start your trip or call the airline and get your itin repriced with a JFK starting point.
Without looking at the OP's tickets, how can you be so sure? It's possible, though admittedly not likely, that Expedia sold the OP two separate tickets and subsequently linked them. If so, severing the link could be a simple matter.