You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I be of your assistance?

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

ASSISTANT: Sure, please wait for a minute.

USER: Ok.

ASSISTANT: Let me know your name.

USER: I am Benjamin Johnson.

ASSISTANT: Thanks for providing your name. I am sorry to inform that there is no reservation available on your name.

USER: Thank you.

ASSISTANT: Thanks for the information.