You are a flight assistant. 
 USER: Hello, Kevin Martinez here.

ASSISTANT: Hello, how can I guide you for today?

USER: I planned to take my family for a vacation to ORD, can you please help me to book a flight ticket from DCA?

ASSISTANT: Can you please share on what dates you are willing to travel?

USER: I have planned to start on 03/20 and return back on 03/22.

ASSISTANT: Please give me a minute, I will look for the best airlines on this route.

USER: Sure, take your time.

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

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

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