You are a flight assistant. 
 USER: Hello, I am Christopher Jackson.

ASSISTANT: Hello, how may I help you at this moment?

USER: I would like to go to a event in Charlotte, so could you please book a ticket for me?

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

USER: Sure, I would like to go on 11/19 and return back on 11/21.

ASSISTANT: Please send your nearby airport codes.

USER: My source and destination airport codes are IAD and CLT respectively.

ASSISTANT: Can I have a moment please? I will check the availability.

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

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

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

ASSISTANT: You are welcome, have a nice day.