You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Myself Joseph hall. I want to book a ticket from DEN to IAH.

ASSISTANT: May I know your preferable dates?

USER: My travelling dates are 07/31 and 08/02.

ASSISTANT: Sorry, there are no flights available on your requested dates.

USER: Thank you.

ASSISTANT: Thank you for choosing us.