How to find available seats

Hi, i wonder if anyone can help me, we are flying from Heathrow to JFK in a couple of weeks, we got a great deal for economy and booked it, however as time as gone on, we think we wold like to upgrade to UC or PE, if available. I do remember reading a thread about a service you have to pay for that allows you to see available seats on flights. Could someone please direct me please thanks X

[preiffer]

Hi Catherine, and welcome.

This thread was discussed extremely recently, around the exact same topic. The Search facility can be a good place to start when looking for new information - someone may have recently asked the exact same thing.

I'll lock this one, to keep things clear - please continue any further questions in the original thread.

Thanks.