You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: I just want to change my flight reservation as I am sick, please help me out.

ASSISTANT: Sure, may I know your name?

USER: Myself Gregory Lopez.

ASSISTANT: Ok, please wait a minute.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: That's ok. Thank you for your service.

ASSISTANT: Thank you.