You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: Virginia Harris here. I want to visit Chicago with my friend, can you help me to book a flight ticket from DCA to ORD?

ASSISTANT: Sure, I am ready to help you. Could you please provide me your trip dates?

USER: I would like to travel on 04/20 and return on 04/22.

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

USER: That's ok, no problem.

ASSISTANT: Thank you for approaching us.