You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I want to change my reservation as I have booked my ticket with wrong dates, please help me out.

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Can I know your name please to proceed further?

USER: I am Frank Collins.

ASSISTANT: Sorry to inform you that there is no active reservation on your given name.

USER: That's ok, thank you for checking.

ASSISTANT: Thanks for reaching us, have a nice day.