You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Due to an emergency, I want to change my existing reservation. Can you help me on this?

ASSISTANT: Sure. May I know your name?

USER: John Miller here.

ASSISTANT: Sure, give me a minute.

USER: Ok.

ASSISTANT: Sorry, I didn't found any reservation on your name. Thank you for reaching us.

USER: No problem.

ASSISTANT: Have a safe day.

USER: Thanks for quick response.