You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you today?

USER: Can you aid me in booking a flight ticket from AUS to DFW?

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

USER: I am planning to start on Apr 22nd and return back on Apr 24th.

ASSISTANT: Ok, do you have any specifications?

USER: I want to depart from my source in evening time and prefer to travel in economy class.

ASSISTANT: Ok, hold on for a moment. Let me check the best available flight for you.

USER: Take your time.

ASSISTANT: May I know your name please?

USER: I am Gregory Turner.

ASSISTANT: Sorry Gregory Turner, there are no flights available on your requested dates.

USER: No issues. Thank you for checking.

ASSISTANT: Welcome, thank you for choosing us. Have a great day.