You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how may I assist you?

USER:  I would like to visit Denver, and participate in the Foothills Explorer tour with my neighbours. Can you help me in booking flight ticket?

ASSISTANT: Sure, I am here to help you. May I know your airport codes please?

USER: My source is from Houston, TX - HOU. Destination is at Denver, CO - DEN.

ASSISTANT: Can you please provide your dates of journey?

USER: My preferable travel dates are 07/20 and 07/22.

ASSISTANT: Ok, hold on for the moment. Let me check.

USER: Make sure that it must be a direct flight. Ok, take your own time.

ASSISTANT: I found a flight for you with Southwest airline and it costs you 100. Shall I proceed?

USER: Sure, please book it.

ASSISTANT: Your ticket has been booked with 1024 flight number.

USER: Thank you for helping me.

ASSISTANT: Thank you for choosing us, have a safe flight.