You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Karen Thomas. Can you help me to book a connecting flight from DCA to MSP?

ASSISTANT: Sure, I am here to assist you. May I know your travel dates?

USER: My travelling dates are 18 and 20 of Mar.

ASSISTANT: May I know your class preference?

USER: I would like to prefer economy class.

ASSISTANT: Ok, do you have any other requirements?

USER: My depart time should be in the afternoon with connection limit.

ASSISTANT: Ok, please wait for a while.

USER: Sure, take your own time.

ASSISTANT: Sorry, there is no flight available as per your given travel dates.

USER: Oh! not a problem, thank you.

ASSISTANT: You are welcome and thank for choosing us.