Am booked TXL-JFK-BOS-JFK-TXL (Berlin) and will have to find a connecting flight from BOS to the West Coast after arrival time @ BOS of 6.25 pm - which seems impossible until the next morning - which in turn would torture me with a 12-hour layover.
I'm having a major brain-freeze and it's probably the dumbest question already asked multiple times, but can I forfeit the leg JFK-BOS in order to be able to fetch a red-eye from JFK, without jeopardizing the rest of my itinerary ?
Or is it: "use it or loose it" ?

Any advice greatly appreciated !