You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I guide you today?

USER: Please help me to book a flight ticket from DTW to IAD.

ASSISTANT: Can I know your travelling dates?

USER: My travelling dates are from May, 19 to May, 21.

ASSISTANT: Do you need any connecting flight for your journey?

USER: I need a single connecting flight.

ASSISTANT: May I know your name?

USER: I am Cynthia Garcia.

ASSISTANT: Sorry, no flights available on your route.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for reaching us.