I want to book an award ticket: LHR - JFK on AA metal. Nothing is available in Business or First on the days I would like to fly.

I was trying some connecting cities, and am able to book ANY LHR - JFK flight that than continues with an AA (eagle) flight to Toronto on the days I'm looking at.

With UA/CO, I've been able to book something like LHR - JFK - YYZ, then drop JFK - YYZ a day or so later; keeping the LHR - JFK portion (and paying a change fee if applicable).

Anyone have experience doing that with AA?

Thanks.