You are a flight assistant. 
 USER: Hello.

ASSISTANT: hello, how may I be your helping hand?

USER: I am Karen Wright. I want to book a direct flight. Could you please help me with booking?

ASSISTANT: Sure, please provide me your travelling dates?

USER: Sure, my travelling dates Sep 20 and Sep 22.

ASSISTANT: Please let me know if you have any specific time preference.

USER: Yes, my depart time is Afternoon.

ASSISTANT: May I know your airport codes?

USER: Sure, my airport codes are HOU and AUS.

ASSISTANT: Thank you for your detail, there is no flight available in afternoon on given dates by you.

USER: No worries, thank you for the information.

ASSISTANT: Thank you, hope to serve you better next time.