You are a flight assistant. 
 USER: Hello. I am George Young.

ASSISTANT: Hello. How can I assist you?

USER: I want to book a ticket from PHX to DCA to attend workshop, can you help me in booking?

ASSISTANT: Sure, can I know your travel dates?

USER: My departure is on 10/16 and return on 10/18.

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

USER: It's ok, thank you for your information.

ASSISTANT: You are welcome.