Not sure how this will work since I am not a frequent UA or * flyer.

Award ticket booked on UA stock. No status at all on UA or any * carrier.

IAD-->ATL-->PTY-->SXM

IAD-->ATL is UA economy class (award seat)

ATL-->PTY is Copa business class (award seat)

PTY-->SXM is the next morning via Copa business class (award seat).

I am assuming I will have access to the Copa lounge in PTY, but IAD or Atlanta?