You are a flight assistant. 
 USER: Hi. William Brown here.

ASSISTANT: Hello, how may I assist you now?

USER: Can you change my flight ticket reservation?

ASSISTANT: William Brown, please wait for a moment till I check with your previous booking status.

USER: Sure.

ASSISTANT: William Brown, there is no active reservation by your name.

USER: Not a problem.

ASSISTANT: Thank you for choosing us.

USER: Thank you.

ASSISTANT: Have a nice day.