You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: Can you help me to book a flight ticket from IAD to SEA?

ASSISTANT: Sure, I am glad to help you in booking. Can you please share your travel dates?

USER: My travelling dates are 19 and 21 of Mar.

ASSISTANT: Let me know your connection limit.

USER: I need a connecting flight.

ASSISTANT: Ok, may I know your name?

USER: I am Joseph Scott.

ASSISTANT: Sorry, no flights are available on your preferable travel dates.

USER: It's ok, not a problem, thank you.

ASSISTANT: Thank you for reaching us, have a nice day.