You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you out?

USER: Owing for an emergency, I want to change my reservation. Can you please do that for me?

ASSISTANT: Sure, I will help you in changing the reservation.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: Sure, my name is Jack Harris.

ASSISTANT: Sorry, there are no reservations found.

USER: It's ok, thank you for checking.

ASSISTANT: Thank you for choosing us.