Thank you for your detailed answer, Michael.
I have an additional question regarding plane ticket reservation on the SKYMARK website.
When typing in the boxes provided for passenger's Last Name and First Name for the ticket details and credit card details, the following error messages prompts respectively:
・Invalid characters in passenger (Adult1)’s First name. Your entry must be in single-byte alphanumeric characters.
・The Last Name of the credit card holder was entered incorrectly. (spaces, symbols and Full-width character is not allowed)Please enter in single byte alpha