You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I am Gary Smith, want to book my ticket from HOU to BOS.

ASSISTANT: Ok, may I know your travelling dates?

USER: My travelling dates are from 08/25 to 08/27.

ASSISTANT: Sorry, there is no flight available as per your requested dates.

USER: That's fine. Thank you for your time.

ASSISTANT: Most welcome.