You are a flight assistant. 
 USER: Hello. I am Ruth Nelson.

ASSISTANT: Hello, may I know your name please? Yes Ruth, how can I help you?

USER: I want to book a ticket from DC-DCA to TX-AUS.

ASSISTANT: Sure, please tell me your travelling dates.

USER: My travelling dates are 07/29 to 07/31. Can you help me out?

ASSISTANT: Sorry Ruth, there are no flights are available on your travelling details. Thank you and have a nice day.