Not all AF PV fares are elegible for SWU upgrade. Only W and S (not A). A is usually the discounted AF fare. Delta sells PV under W fare and usually, the price corresponds to the AF A (discount). It is therefore usually a better deal to buy Delta W fare (either calling the Medallion line and hoping to talk to an agent who knows what he's doing or directly on delta.com) and calling to process the upgrade using the SWU.
You can also buy the AF W or S (often more expensive), then call the medallion line.

Another advantage of buying the delta ticket is that you can cancel it within 24hrs without penalties. Therefore, should O disappears in the meantime or should there be any other issue, you can just cancel and not worry about it. trying to cancel a non refundable fare bought on AF (even 1 min after buying it) is challenging if not impossible (I succeeded once but it took a lot of time and convincing).

Finally, once the upgrade is processed, ask the agent to be transferred to the skyteam desk so that they re-issue your ticket immediately. Better safe than sorry. I would recommend doing so and not letting delta put your re-issue in the queue as bad things have happened.


Good luck