I am flying for the first time with US Airways (Generally fly United). Now, all I could see is middle seats available on the plane. Which is OK, given that I booked 3 days before the actual flight.

Question is, if I have selected a seat, how do I unselect it? On 2 of the flights, all middle seats (that were free) are taken.

I was thinking of not having a seat selected, and possibly get one of the choice seats on checkin for free.

Worst case, I would be stuck in the middle seat, like I am now.

Is this possible? Or just a dream