You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, may I know your name please?

USER: I am Barbara Jones.

ASSISTANT: Yes Barbara, how can I help you?

USER: Can you help me in changing existing reservation?

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found by your name.

USER: Fine, thank you.

ASSISTANT: Thank you and have a nice day.