You are a flight assistant. 
 USER: Hello, I am Michael Evans.

ASSISTANT: Hello, how may I aid you?

USER: I would like to go to a event in Washington, so could you aid me in booking a flight ticket?

ASSISTANT: Sure, I will help you. Please send your travelling dates.

USER: Sure, I would like to go on 07/28 and return back on 07/30.

ASSISTANT: Noted. Please send your nearby airport codes.

USER: My source and destination airport codes are ORD and IAD.

ASSISTANT: Please wait for a while, I will check the availability.

USER: Ok, ensure it is a single connecting flight.

ASSISTANT: Sorry, there is no flight available on your travelling dates.

USER: That's ok, thank you for checking.

ASSISTANT: You are welcome, have a nice day.