You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

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

ASSISTANT: Sure, I will help you to change your existing reservation. May I know your name?

USER: I am Katherine Phillips.

ASSISTANT: Please give me a moment.

USER: Ok.

ASSISTANT: Sorry, no reservation found on your name to change your reservation.

USER: Thanks.

ASSISTANT: Welcome, have a nice day.