You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you at this moment?

USER: I would like to do some modifications in my existing reservation, can you help me in that/.

ASSISTANT: Sure, I will help you. Please wait for a moment.

USER: Thank you.

ASSISTANT: May I know your name?

USER: Sure, myself Ruth Roberts.

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

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

ASSISTANT: You are welcome, have a nice day.