You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: Can you help me to book a flight from DCA to LAS?

ASSISTANT: Sure, may I know your name?

USER: My name is Jack Lee.

ASSISTANT: Sure, could you please help me with your travelling dates?

USER: My travelling dates are 12/22 and 12/24.

ASSISTANT: May I know your other specifications?

USER: I prefer connecting flight.

ASSISTANT: There is a flight on Southwest airline, flight number 1015 with the fare of 300.

USER: Proceed with booking.

ASSISTANT: Your ticket has been booked.

USER: Thank you.

ASSISTANT: Thank you for choosing us.