You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Can you please help me in booking my ticket from ORD to DCA?

ASSISTANT: May I know your trip dates?

USER: Sure, my trip dates are from 06/27 to 06/29.

ASSISTANT: Do you have any other requirements?

USER: Yes, I need a direct flight.

ASSISTANT: May I know your name please?

USER: Myself Sandra Lopez.

ASSISTANT: Sorry, we regret to inform you that there is no flight available as per your request.

USER: It's ok, thank you for your help.

ASSISTANT: Most welcome.