I have a same day trip on CO, but I could only check in for the outbound so far. The return portion is within 24 hours but unlike UA.bomb, CO website does not show an option for additional flights. It keeps saying I have already checked in... Am I missing something? If not, when may I print out the return BP?

I have a short turn around time, so I would like to print out boarding passes in advance...

Thanks,
Teddy