You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you?

USER: My name is Paul Brown. Please change my existing reservation, as my music concert dates have been postponed to some other dates.

ASSISTANT: Paul, I will help you, please give me a moment. Sorry to inform you that there is no reservation found under your name.

USER: That's ok, may be my reservation did not done properly.

ASSISTANT: Can I help you with anything else?

USER: No, thank you for your time.

ASSISTANT: Thank you for reaching us, have a nice day.