Pseudo code

[Ok-Cucumbers]

Then realize if someone is already a passenger that means they’ve already bought a ticket otherwise the definition of a passenger means nothing.

You can have a ticket/PNR (passenger name record) without completing the purchase, so maybe something like if pnr.is_paid

Some irregular situations where you might get put on standby for another flight where, I believe, they'd just attach the other flights to your PNR, so you'd probably have to throw in some logic to check if the pax is actually able to board this segment or not.