Originally Posted by cfischer

1) 24 hours prior for NH flights these days
2) UA will send an Email that it has cleared, but just in case, I'd check NH as well since the Email notification is sometimes broken
3) Nothing. You are all set. DO NOT ask for ticket re-issues. Call NH or check online and get yourself a seat in the upgraded cabin. Print any confirmation of the UGed cabin from NH in case there are challenges when checking in at the airport (rare, but it does happen)