no one can exchange for u, there is a name on each ticket,name should match with the name on ur passport. the only way u can do is..... call the airline company to find out if there is a seat for u
they still can't exchange for you, because ur friend's seat will go to the system and there is a waiting list, airline company can't just simply give that seat to u..my suggestion is call the airline company and check if they can't change the schedule for u