You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you at this moment?

USER: I want to book a ticket from DFW to HOU. Could you book a ticket?

ASSISTANT: Sure, I will help you with that. Can I have your travel dates please?

USER: Departure is on July, 23 and return date is July, 25.

ASSISTANT: Ok, please let me know the timings of your journey.

USER: I would like to return in the evening time.

ASSISTANT: Do you have any more specifications?

USER: I prefer connecting flight.

ASSISTANT: Can I have your good name please?

USER: My name is David Lewis.

ASSISTANT: Sorry to inform you that no flight is available in your route on your dates.

USER: Thank you.

ASSISTANT: Thank you for choosing us, have a good day.