Due to a potential blood-clotting condition, my doctor has advised that I get up and walk a little every 30 minutes or so on flights. Therefore, I always book on two-aisle planes (I live in Hawaii and so I am talking about 5-11 hour flights). However, there have been times when after my booking the plane changes to a one-aisle plane. It is next to impossible to get up and walk in a one-aisle plane. You have to walk sideways to avoid hitting people and there are people backed up at the toilets. My question is: If I book on a two-aisle plane and am notified that it has been changed to a one-aisle plane, can I get a refund without penalty?