You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Can you please help me to book a ticket from DCA to ORD?

ASSISTANT: Sure, I am here to help you. May I know your planned trip dates?

USER: My travelling dates are on Apr 08 and Apr 10.

ASSISTANT: Do you have any class preference?

USER: No.

ASSISTANT: Are you looking for a connecting flight or a direct flight?

USER: I need a connecting flight.

ASSISTANT: Can you please share your name to proceed further?

USER: My name is Gregory Green.

ASSISTANT: Sorry, there is no flight available on this route for the given dates.

USER: Ok, thank you for informing me.

ASSISTANT: Thank you for reaching us.