You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: Can you please book a flight ticket from IAD to ATL?

ASSISTANT: Please provide your travelling dates?

USER: My trip is in Dec from 3rd to 5th.

ASSISTANT: Do you have any preference?

USER: I prefer to board a direct flight.

ASSISTANT: May I know your name?

USER: Anna Moore here.

ASSISTANT: Sorry, there is no flight for your travelling dates.

USER: That's ok, thank you for your information.

ASSISTANT: Thank you.