You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you now?

USER: I want to change my existing reservation. Could you help me with that?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: May I know your good name?

USER: Daniel Brown here.

ASSISTANT: Please wait for a moment.

USER: Ok.

ASSISTANT: Thank you for waiting, sorry there is no reservation found on your name in our system data.

USER: That's ok, no problem. Thank you.

ASSISTANT: Thank you for visiting us, have a nice day ahead.