You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: I need you to book a flight ticket from EWR to DCA.

ASSISTANT: Sure, can you please share your travel dates?

USER: April 21 and 23 are my planned travelling dates.

ASSISTANT: Do you have any connection limit?

USER: I need a connecting flight.

ASSISTANT: May I know your airline preference?

USER: I need a normal-cost airlines.

ASSISTANT: In which class do you prefer to travel?

USER: I prefer to fly in a economy class.

ASSISTANT: Do you have any other requirements?

USER: Nothing much to state.

ASSISTANT: May I know your name please?

USER: Debra Brown here.

ASSISTANT: Sorry, there are no flights in this route as per your travelling details.

USER: That's ok. Thank you.

ASSISTANT: Thank you for choosing us.