You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am Patricia Thompson. I am planning to attend music concert at LAS, can you please help me with booking a flight ticket from DCA?

ASSISTANT: May I know your desired travel dates please?

USER: Sure, I would like to take off on 01/9 and return on 01/11.

ASSISTANT: Sorry to say, there is no flight on your desired travel dates.

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

ASSISTANT: Thank you for opting us.

USER: You are welcome.