with a different PNR it's not possible even if you call customer services. The online check in shows different results too for me (emerald / BA gold) and my companion (no status). There were plenty of seats available in expert flyer that showed "occupied" in the seat map and some seats (like the exit rows) were free but "occupied" in my AY seat map, but available for her (at a cost) even though the exit row seats are free for me and chargeable for non-status card holders (this is at check-in, not advance seat reservation). So it was quite hard to get two seats together even though many such seats were actually available but showing as "occupied" by AY online check in. AY customer service is no help at this point, because they see the same theoretical seating availability rather than real seat availability.