Simple question I think that I am making more complex than it should be. I am on an itin that has four segments (2 there, 2 back). It was booked on UA and only the first segment is on UA metal. The other three segments are on CO metal booked as UA code shares (though two of those are on CO Express, thus no upgrades). Do I have to do anything to get on the CO upgrade waitlist for the UDU equivalent for the one CO segment that matters? Should I CO status match and somehow split up the earning miles portion to get higher priority, is that possible?