Ach misread things - it is about taking a later CDG-BKK flight, not a later ex-LAX flight. You can always ask when you are in the CDG lounge but do not give it a lot of chance unless you happen to be in a flexible fare bucket (and then I would try it now, right away by calling). Once I had the experience they were ok booking me on an earlier flight when I arrived early at the airport (was afraid for long queues during the AMS summer mess). I think they were ok since they reckoned they never could sell a seat still open on a flight 60 min later, where for the flight a few hours later they still had a chance on a sales, or use it for some diverted pax. The other way around would limit this flexibility.