You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you today?

USER: I am Gary Evans.

ASSISTANT: Ok.

USER: Can you please help me in booking my flight ticket from Austin AUS to Denver DEN?

ASSISTANT: Sure, we are here to help you. May I know your travelling dates?

USER: My travelling dates are Apr 28 and Apr 30.

ASSISTANT: Do you prefer any halt in between your journey?

USER: I need halt in between my journey.

ASSISTANT: Is there any other preferences?

USER: No, I do not have any other preference.

ASSISTANT: Ok, please wait for a while.

USER: Ok, sure.

ASSISTANT: Sorry, there are no flights found from your source on given dates.

USER: Ok, fine thank you for checking.

ASSISTANT: Thank you for availing us.