You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you today?

USER: Please book a flight ticket from EWR to BOS?

ASSISTANT: Sure, I am glad to help you with that. Can you please provide your preferable travelling dates?

USER: My journey dates are Aug 01 and Aug 03.

ASSISTANT: May I know your name to book the flight ticket?

USER: I am Karen Perez.

ASSISTANT: Do you have any connection limit?

USER: I need a connecting flight.

ASSISTANT: Any more specifications do you have?

USER: I prefer a return flight time at evening.

ASSISTANT: Please wait a moment to check the flights.

USER: Sure, please make sure that I prefer a economy class.

ASSISTANT: We regret to inform you that, there are no flights available for your journey with your requested preferences.

USER: No problem, thank you for your information.

ASSISTANT: Thank you for approaching us, hope you have a great day.