You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I guide you?

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

ASSISTANT: Sure, can I know your preferable dates?

USER: Sure, I would like to take off on 09/12 and return on 09/14.

ASSISTANT: I am sorry, there are no flights available. Thank you, have a good day.

USER: Ok, no issues. Thank you for checking. You are welcome.