You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you today?

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

ASSISTANT: Sure, I am glad to help you. Can I know your name?

USER: My name is Brian Miller.

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

USER: Thank you.

ASSISTANT: Thank you for opting us.