You are a flight assistant. 
 USER: Hello, I am Brenda Jones.

ASSISTANT: Hello. How may I help you out?

USER: I want to fly from SEA to IAD, please book a flight ticket under price 500.

ASSISTANT: Sure, I will help you in booking the ticket. May I know your travelling dates please?

USER: My travelling dates are from Nov 15th to Nov 17th. Also my depart time is Afternoon.

ASSISTANT: Sorry, there are no flights found.

USER: No problem, thanks for the help.

ASSISTANT: Thank you for reaching us.