You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I'm Ryan Parker.

ASSISTANT: How can I help you?

USER: I am planning to attend National Art museum at Washington, can you please help me with booking a flight ticket?

ASSISTANT: Sure, help me with the travelling dates.

USER: Sure, I would like to take off on 12/31 and return back on 01/02.

ASSISTANT: May I know your travelling airport codes of journey?

USER: My source airport code is PHX and the destination airport code is IAD.

ASSISTANT: Give me a minute.

USER: Ok, but please make sure that the price limit does not exceed 200.

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

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

ASSISTANT: Thank you for opting us.