You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: Please help me to book a flight ticket from DEN to DCA.

ASSISTANT: Sure, may I know your travelling dates?

USER: I will start on Nov, 18 and return on Nov, 20.

ASSISTANT: May I know your name?

USER: Linda Wilson here.

ASSISTANT: Do you need any specifications?

USER: I am looking for connecting flight.

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

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

ASSISTANT: Thank you for reaching our service.