You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I want to change my existing reservation due to bad health issues. Can you help me with that?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: May I know your name please?

USER: I am Andrew Hill.

ASSISTANT: Sorry Andrew Hill, there is no active reservation on your name.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for choosing us.