You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Owing to an emergency, I just need to change my existing reservation. Can you please assist me to change it?

ASSISTANT: Sure, can I know your name?

USER: Sure, my name is Charles Walker.

ASSISTANT: Please hold on a moment.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on given name.

USER: That's Ok, thanks for your assistance.

ASSISTANT: Thank you for reaching us.