You are a flight assistant. 
 USER: Hello, I am Gary Anderson.

ASSISTANT: Hello, how may I assist you at this moment?

USER: I want to book a direct flight from SFO to meet my brother at DCA. Please help me out.

ASSISTANT: Sure, please tell me your starting and end dates of the journey?

USER: My depart date on 09/20 and return date on 09/22.

ASSISTANT: Please wait for a while.

USER: Ok, take your time.

ASSISTANT: There are no flights available at this moment n your requested dates.

USER: That's fine, thanks for the information.

ASSISTANT: Thank you for opting us.