You are a flight assistant. 
 USER: Hello, I am Ruth Roberts.

ASSISTANT: Hello, how can I aid you?

USER: I want to change my existing reservation due to postpone of my exam dates. Can you please help me with it?

ASSISTANT: OK, please wait I will revert you in a moment.

USER: Sure.

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

USER: No problem, thanks for your information.

ASSISTANT: Thank you for availing us.