You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I would like to do some changes in my existing reservation. Can you help me for that?

ASSISTANT: May I know your name please?

USER: My name is Brandon Thomas.

ASSISTANT: Sorry to inform you that no reservation found with your name.

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

ASSISTANT: Thank you for reaching us.