Hello, I purchased the Eurail Global Pass for 10 days in 2 months. It turns out I will only be needing about 6 or 7 trains. Is there a way after my trip if I only used this many to refund down to the 7 days pass? If not should I cancel my pass and buy a new one now or just leave it? (I have already reserved the Eurostar using this 10 day pass)