You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, What can I do for you?

USER: I want to change my existing reservation, due to some health issue. Can you please help me out?

ASSISTANT: Sure, May I know your name?

USER: My name is Elizabeth Davis.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry, No reservation found on your name.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for opting us.