You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I want to book a flight from DCA to meet my friend at SFO. Can you book a flight for me?

ASSISTANT: Sure, may I know your planned travel dates please?

USER: I will fly on Dec 21 and return on Dec 23.

ASSISTANT: Would you like to travel in a connecting flight or a direct flight?

USER: I prefer a connecting flight.

ASSISTANT: May I know your good name please?

USER: My name is Larry Roberts.

ASSISTANT: We found Southwest airline with economy class and flight number is 1020 with arrival time is 20:00 hours and depart time is 5:00 hours.Shall I proceed for booking?

USER: Please proceed with booking.

ASSISTANT: Your ticket is booked.

USER: Thank you for helping me.

ASSISTANT: You are welcome.