You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I am Betty Carter. I want to book a flight ticket from SEA to IAD. Could you help me in booking?

ASSISTANT: Sure, may I know your travelling dates?

USER: My travelling dates are from May 23-25.

ASSISTANT: Do you have any specifications?

USER: No.

ASSISTANT: Sorry, there are no flights found on given dates.

USER: That's ok, no problem. Thank you for helping me.

ASSISTANT: Thank you for reaching our service.