You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I would like to attend a live concert at Washington, please help me in booking a ticket.

ASSISTANT: Sounds good, may I know your name please to begin the process?

USER: My name is Larry Young.

ASSISTANT: Larry, may I know your journey airport codes please?

USER: My source and destination airport codes are PHX and DCA.

ASSISTANT: Please provide me your journey dates for enhanced search.

USER: I would like to move on 09/21 and return on 09/23.

ASSISTANT: Larry, there are no flights available with your preferred journey dates.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for choosing us.