You are a flight assistant. 
 USER: Hello, I am Michael Allen.

ASSISTANT: Hello, how may I assist you?

USER: Can you aid me in booking a flight ticket from DFW to MSP?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Can you share me your travel dates?

USER: Sure, I would like to go on Dec 20th and return back on Dec 22nd.

ASSISTANT: Do you prefer connecting flight or direct flight?

USER: Ensure it is a single connecting flight.

ASSISTANT: May I know your depart time and arrival time?

USER: Ensure the return time is in the evening.

ASSISTANT: Do you have any other preferences?

USER: No, I don't have any other requirements.

ASSISTANT: Sorry to inform you that, there are no flights available with your requirements.

USER: That's ok, thank you for checking the availability.

ASSISTANT: Thank you for availing us.

USER: Welcome.