You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: I am Dennis Williams, want to travel from IAD to BOS. Please help me in booking my ticket.

ASSISTANT: Sure, I can help you with that. May I know your preferable journey dates?

USER: Sure, my trip dates are from 11/21 to 11/23.

ASSISTANT: Ok, please wait for a while.

USER: Please check the flight with 1 connection and the fare should not exceed more than 500.

ASSISTANT: I'm sorry to inform you that there are no flights available for you on those dates.

USER: It's ok, no issue. Thank you for your help.

ASSISTANT: Thank you for choosing us to serve you in ticket booking.