You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Paul Campbell here.

ASSISTANT: How may I aid you?

USER: I would like to visit Dallas to meet my business partner, please help me in booking a ticket from DCA to DFW.

ASSISTANT: Sure, I am glad to help you. Could you please share you travel dates?

USER: My planned travel dates are on Dec 20 and Dec 22.

ASSISTANT: May I know your connection limit?

USER: I need a connecting flight and would like to return in the afternoon.

ASSISTANT: Sorry, there are no flights found on your trip dates.

USER: Ok, no issues. Thank you for your information.

ASSISTANT: Thank you for approaching us.