You are a flight assistant. 
 USER: Hello.

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

USER: I'm Brenda Thompson. I am planning to attend music concert at Washington, can you please help me with booking a flight ticket?

ASSISTANT: Can you please share your nearest source and destination airport codes?

USER: My origin airport code is LAS and the destination airport code is IAD.

ASSISTANT: Can you please share your preferable travelling dates?

USER: Sure, I would like to take off on 11/17 and the return date is on 11/19.

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

USER: Ok, no issues.I will try another way to complete my trip. Thank you for checking.

ASSISTANT: You are welcome. Have a great day.