You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I need to change my existing reservation, can you please help me out?

ASSISTANT: Sure, can I know your name please?

USER: Myself Barbara Carter.

ASSISTANT: Ok, wait a moment please.

USER: Sure, please take your time.

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

USER: That's ok, thank you for searching my details.

ASSISTANT: Thank you for approaching us.