I'm having a tough problem:
A Korean lady living in New Zealand has just gotten naturalised and has a New Zealand passport. She used her South Korean passport (with her resident visa) the last time she entered New Zealand, because at that time she wasn't a New Zealander.
My question is: the next time she exits New Zealand to go back to Korea, what passport should she use?
Should she use her Korean passport, because one should enter and exit a country using the same passport?
Or should she use her New Zealand passport, because she is a New Zealander? And if she's not using the New Zealand passport to exit the country, upon coming back to NZ she will have hard time with border patrol because her New Zealand passport will not have the depart stamp on it?
To complicate things further, the lady has two different names on her two passports. The Korean one is for Ko Un-Ha but her New Zealand passport is for Michelle Stevenson (these are fictitious names to show how different they are). What names should be on the flight tickets?
Just to clear up the situation: The lady got naturalised by marriage. Under Korean law she is allowed to keep her Korean nationality, so both of her passports are valid.