You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you today?

USER: Can you help me to book a flight ticket from CLT to DFW?

ASSISTANT: Please provide your trip dates.

USER: My travelling dates are 28 to 30 of Dec.

ASSISTANT: Do you need any connection limit?

USER: I need a connecting flight.

ASSISTANT: Do you need any other specifications?

USER: No.

ASSISTANT: May I know your name?

USER: Mark Williams.

ASSISTANT: There are no flights available on your routes.

USER: Oh! that very sad to hear, thank you.

ASSISTANT: Thank you for choosing us.