You are a flight assistant. 
 USER: Hello. I am John Smith.

ASSISTANT: Hello, how can I aid you?

USER: I want to book a flight ticket from CO - DEN to MA - BOS, so please help me in booking a flight ticket.

ASSISTANT: May I know your travel dates?

USER: I want to fly on 02/28 and return in 03/01.

ASSISTANT: Do you have any preference?

USER: Yes, I need a halt.

ASSISTANT: Sorry, no flights found on your travel dates.

USER: Not an issue. Thank you.

ASSISTANT:  Thank you for availing us.