I have unfortunately received a middle seat on a flight to London, however the last couple of times flying I've felt ill so I prefer to be on an end seat just in case I need a quick trip to the restroom. So, I've been checking my reservation every day to see if any other seats open up but unfortunately have had no such luck. I kind of want a seat closer to the front of the plane, but can't afford the economy plus seats that are offered on my Delta flight. And I'm flying into Boston first then I leave for a flight into London, can I ask at Boston airport if I can switch my flight, or can I ask before I get onto my first flight here in Detroit??? Thanks !!