You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

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

ASSISTANT: Please provide your trip dates.

USER: My travel dates are 22 to 24 of Dec.

ASSISTANT: Do you need any connection limit?

USER: I need a connecting flight.

ASSISTANT: Do you have any specifications?

USER: I would like to depart in the evening and return in the morning.

ASSISTANT: May I know your name?

USER: I am Richard Green.

ASSISTANT: There are no flights available on your routes.

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

ASSISTANT: Thank you for choosing us.