Originally Posted by CPH-Flyer

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To put it bluntly, unless the waitlist clears, you have no tickets and will not fly ORD NRT. You don't have a ticket until the waitlist clears.

You can probably split the booking so you can book a different class for the return. But two passengers on one PNR will need to be booked in the same fare class. I am not sure if you can change the waitlist from F to J without cancelling, but you would certainly need to call in and have an agent try.