You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you today?

USER: I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: Barbara Baker here.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry to inform you that, there is no reservation found as per your name.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for reaching us with a query.