You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: My name is Justin Lewis, can you please book me a flight ticket from DCA to EWR? Sure, my trip dates are from 11/09 to 11/11.

ASSISTANT: Sure, can you please tell your travelling dates? Sorry, there are no flights available with your requested details.

USER: That's ok, thank you for the information.

ASSISTANT: Thank you and have a nice day.