You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Williams Collins here. Can you please book me a flight from DEN to visit DCA?

ASSISTANT: Sure, I am glad to help you. Can I have your planned trip dates?

USER: Sure, my travel dates are Sep 24th and 26th.

ASSISTANT: Do you have any other specifications?

USER: I need a single connecting flight. My depart time must be in the morning.

ASSISTANT: Please wait for a minute.

USER: Ok, sure.

ASSISTANT: Sorry to say that, there are no flight's available based on your journey details.

USER: Ok, not a problem. Anyways, thank you.

ASSISTANT: Thank you for consulting us.