Using miles to upgrade on AF from W to O?
I'm purchasing a ticket on Delta r/t from MCO-CDG, via ATL. AF is operating the ATL-CDG route. I'd like to purchase W (prem econ in separate cabin), and use miles to purchase upgrade to biz. I have researched and can't find something updated that tells me the best way to do this. I understand that there needs to be O class availability. Is there a way to find out? I can't seem to find it on the AF website either. I haven't purchased yet but there is plenty of W available on several flights. Departing Nov 8 and returning Nov 14. Any suggestions? Thank you!!