You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: I have a business meeting in DEN, can you please book a flight ticket from DCA?

ASSISTANT: Ok, please help me with your trip dates.

USER: I have meeting on 03/20 so my departure date is 03/19 and please book my return ticket also on 03/21.

ASSISTANT: May I know your name please?

USER: Sure, my name is John Hernandez.

ASSISTANT: John, no flights has been found on your journey dates.

USER: It's ok no problem, I will go with another airline.

ASSISTANT: Thank you for choosing us.

USER: Thank you for your information.