You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: Could you please book a flight ticket from IAH to IAD?

ASSISTANT: Sure, I am happy to help you. Can you please let me know your travelling dates?

USER: My travelling dates are Aug 23 and Aug 25.

ASSISTANT: Do you have any other specifications?

USER: I need a connecting flight. And I prefer a business class.

ASSISTANT: May I know your good name?

USER: I am Charles Gonzalez.

ASSISTANT: Sorry, no flights are available on your journey routes.

USER: Not a problem, thank you for the information.