You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I'm Frank Hall planning my vacation in Boston, can you book a ticket from AUS to BOS?

ASSISTANT: Please provide the travelling dates.

USER: Sure, my travel dates are 06/13 and 06/15.

ASSISTANT: Sorry, there is no flight available.

USER: OK, thank you.

ASSISTANT: Thank you for contacting.