I am sure this is somewhere but I cannot find it for the life of me.

This is my first time flying Continental (no CO status) and I am wondering how the First Class Upgrade will work? Will it be before I get to the airport like when I fly with United (5 Days before)? Or is there a different protocol when flying CO?

I am flying from DEN to LAS and I dont see the usual "Upgrade Pending" next to my confirmation online like when I fly on United...

Please advise!!!!