You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: I want to schedule my trip from BOS to DFW, can you please book me a flight ticket?

ASSISTANT: Please provide your trip dates.

USER: My trip dates are from Nov 21st to Nov 23rd.

ASSISTANT: Do you need any connection limit?

USER: I prefer a direct flight to travel.

ASSISTANT: Do you need any other requirements?

USER: No.

ASSISTANT: May I know your name?

USER: I am David Carter.

ASSISTANT: There are no flights available on your dates.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for opting us.