You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you today?

USER: I want to change my existing reservation owing to an emergency.

ASSISTANT: Sure, I am mirthful to help you with that. May I know your name?

USER: I am Dennis King.

ASSISTANT: Sorry, no reservation found on your name.

USER: Thank you.

ASSISTANT: Thank you for reaching us, have a nice day.