You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you now?

USER: Can you please help me to book a flight ticket from PHX to HOU?

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

USER: I am happy for your response. My travel dates are Dec 13 and Dec 15.

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

USER: No but I prefer a direct flight to travel.

ASSISTANT: Do you prefer any other specifications to get best flight for you?

USER: No, I didn't have any other specifications.

ASSISTANT: Can I have your good name please?

USER: My name is Richard Carter.

ASSISTANT: Sorry to infirm you that no direct flight is available to you on your dates.

USER: It's ok, not an issue. I will choose some other source to travel. Anyways thank you for searching the flights.

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

USER: You are welcome.