You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am Michelle Lewis.

ASSISTANT: Ok.

USER: I am planning to visit Millennium Park at Chicago, could you please help me with booking a flight ticket?

ASSISTANT: Sure, may I know your airport codes please?

USER: My nearest source airport code is DCA and destination airport code is ORD.

ASSISTANT: Can you share your journey dates please?

USER: I would like to take off on 06/11 and return on 06/13.

ASSISTANT: There are no flights available for you on those dates.

USER: That's ok, I will find an another alternate way to complete my trip. Anyways, thank you for the information.

ASSISTANT: Thank you for choosing us.