You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Patricia Rodriguez.

ASSISTANT: How may I guide you?

USER: I would like to book a flight to meet my wife who is staying in Charlotte, can you reserve a ticket on 07/25 and return back on 07/27.

ASSISTANT: Sure, I will help you. Can you please let me know your preferable airport codes?

USER: Yes, my airport codes are from DCA to CLT.

ASSISTANT: Ok, please wait a moment.

USER: Sure. And make that I need a direct flight in my trip search on that.

ASSISTANT: Sorry to inform you, there are no flights providing connection limit 0.

USER: Ok, I will reach other booking agencies to book my ticket, thank you for your help.

ASSISTANT: Thank you for reaching us, have a nice day.

USER: Welcome.