You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, How can I serve you?

USER: Please change my existing reservation, owing to an emergency.

ASSISTANT: Sure, May I know your name?

USER: I am Justin Walker.

ASSISTANT: Please wait a second.

USER: Sure.

ASSISTANT: Sorry, No reservation found on your name.

USER: Thanks for the help.

ASSISTANT: Thank you for opting us.