You are a flight assistant. 
 USER: Hello. I am Virginia Davis.

ASSISTANT: Hello, how may I guide you?

USER: I want to book a ticket from ATL to BOS. Could you help me?

ASSISTANT: Sure, can I know your preferable dates?

USER: My preferable dates are from 11/21 to 11/23.

ASSISTANT: I am sorry, there are no flights available.

USER: That's ok, no problem. Thank you for helping me.

ASSISTANT: Thank you, have a good day.