You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you today?

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

ASSISTANT: Ok, May I know your name to find the existing reservation?

USER: My name is Patrick Lee.

ASSISTANT: Please wait.

USER: Ok.

ASSISTANT: Sorry to inform you that there is no reservation found under your name to change.

USER: Thank you.

ASSISTANT: Thank you for opting us.