Originally Posted by
CMTinPHL
The easiest thing to do is to clear immigration and customs, and then go to the transit counter / bag drop and ask the agents there to just put you on the earlier flight. If space is available, they often will just confirm you on the earlier flight. You also know for a fact that you are going to make it.
the links posted earlier said that agents will not longer be able to put you on an earlier flight. You have to do it online basically