You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

USER: I am Janet Walker want to visit Austin, can you help me to book a direct flight?

ASSISTANT: I am glad to help you, can I know your journey dates?

USER: Sure, my travelling dates will be 06/22 and 06/24.

ASSISTANT: Can I know your origin and destination airport codes?

USER: Yes, I want to travel from HOU to AUS.

ASSISTANT: Ok, please wait for a while.

USER: Ok.

ASSISTANT: Sorry, no flights available on your given dates.

USER: That's ok, thank you.

ASSISTANT: Thank you very much for choosing us and have a nice day.