Agree. I once had a rerouting SV->Turkish and the ticket number did not even change. Maybe you can check in which booking class they put you on AF (I could see a Turkish PNR and use manage my booking at Turkish for seat selection, and so on). If that is a flexible fare bucket, maybe you can play it via AF by contacting them. But I guess chances are slim it works that way and that you have been rebooked in a fare class that does not allow changes, or only at a cost. And maybe AF will refuse to touch the ticket since it is provided by SV.

I assume the reason for the question is that given your nickname you are from Vancouver and need to position to LAX, and you feel safer by combining an early morning positioning flight with a later AF flight. In many ways it is so much safer to do this with a night in between.