You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I am Richard Roberts, want to travel from AUS to ATL. Please help me in booking my ticket.

ASSISTANT: Sure, may I know your trip dates?

USER: Sure, my travelling dates are from 09/11 to 09/13.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, there is no flights available.

USER: It's ok, thank you for your help.

ASSISTANT: Most welcome.