Can someone return a M11x after the first few days of purchase?

I am trying to help someone who has recently purchased an aleinware M11x in the last few days however the m14x just came out and they want to know if and how it is posible to return the m11x for cash, or a direct exchange for the m14x (adding the extra cash of course). any (sensible) answers are appreciated and helpful but I am looking for an exact procedure on how to do this (eg. call them or send an email, go onto some sort of forum... any ideas/solutions)