Passport Information

Booking flights with China Airlines and Eva Air and both airlines ask for my passport number which I do not have. It is in the process of being renewed and I saw online that you can always change the passport number before the actual date of the flight. I saw another that said you can put zero's and everything will be fine that way as well. I want to book the flight soon before prices go up, but still waiting a while for my passport.

So is it possible to put in zeros or a random set of numbers on the reservation and check in using the valid passport? Would the flight be cancelled automatically if it detects an invalid passport number?

edit: China Airlines (TPE -> SGN)

Eva Air (SGN - SFO)

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