You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I serve you?

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

ASSISTANT: Sure. May I know your name please?

USER: My name is Donald Lee.

ASSISTANT: Please wait.

USER: Ok.

ASSISTANT: Sorry to inform you that I have not found your flight reservation to change it.

USER: Thank you.