You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you at this moment?

USER: I want to reach DCA, as I have my brother's wedding. Can you please help me out in reserving my flight from ORD?

ASSISTANT: Sure, I am here to help you out. Can you please share your travelling dates?

USER: Thank you, my travelling dates are Aug 28th and Aug 30th.

ASSISTANT: Do you have any connection limit?

USER: I am comfortable either with a direct flight or a connecting flight.

ASSISTANT: May I know your departure and arrival time?

USER: I would like to return in the afternoon time.

ASSISTANT: Do you have any other requirements?

USER: No.

ASSISTANT: May I know your name please?

USER: I am Michael Green.

ASSISTANT: Sorry, there are no flights in this route as per your travelling details.

USER: Ok, no problem. Anyways, thank you for the information.

ASSISTANT: Thank you for choosing us.