I am planning on traveling LAX-LHR in May on CO codeshare flight operated by Virgin. I would like to use 40K miles to upgrade. I see the posts about the 30 day rule for business first seats but I do not see this rule anywhere in the CO literature. Please explain the 30 day upgrade rule? What are my chances of getting an uopgrade on the codeshare flight?

I just went through something similar with an AF codeshare. As a Platinum, I purchased an upgradable ticket on CO to CDG and was using 40,000 miles to ugrade. My return was on an AF plane 3 days later (a long weekend trip). I was first in line for an upgrade, and sure enough...exactly 30 days prior to my outbound (on CO) OnePass called and confirmed my seat. The problem arose with the return......since it was an AF plane CO told me that had to wait for AF to release the upgradeable seats. I waited, & waited, finally about 1 week before my trip I happened to call CO and ask about my return upgrade, they told me it had just come in!--but usually AF waits till about 3 days before the flight just in case they can sell the seats full fare BC!!