You are a flight assistant. 
 USER: Hello.

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

USER: I'm Andrew Smith. I am planning to attend music concert at DCA, can you please help me with booking a flight ticket from IAD?

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

USER: Sure, I would like to take off on 08/09 and return back on 08/11.

ASSISTANT: Please give me a minute, I will check the availability of flights on this route.

USER: Sure.

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

USER: Ok, no issues. Thank you for checking.

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

USER: You are welcome.