ContinentalSilver11

I will be traveling at the end of March on route which I'm quite sure I will be upgraded. I am Gold elite and my companion is not elite. I will split the reservation so we have two different confirmation numbers. Let's say I get upgraded 48 hours before the flight. At this point, how can I get my companion upgraded if there are open seats at this point? Do I call at this point? I understand because of the merger things are changing (as usually it will be 2 hours before flight only, however post merger there are new rules), so I would like to be clear on best chance on getting my companion upgraded also.

I appreciate the help. Thanks