You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you?

USER: I am William Collins. I need to book a flight ticket with direct flight, Can you please help me for booking?

ASSISTANT: Sure, can you share your trip dates?

USER: I would like to travel on 05/20 to 05/22.

ASSISTANT: May I know your airport codes?

USER: My source point is IAH and DFW.

ASSISTANT: Do you have any specifications?

USER: I need a price limit 500.

ASSISTANT: There is a connecting flight with number 1009 in airline Southwest, the fare is 100. Can I book it?

USER: Ok, proceed for booking.

ASSISTANT: Your ticket is booked.

USER: Thanks for your information.

ASSISTANT: Thank you for availing us.