You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I am planning to visit Olympic National Park at Washington, could you please help me with booking a flight ticket from CLT to DCA?

ASSISTANT: Sure, can you please share your travel dates?

USER: I would like to depart on Mar 31st and return on Apr 2nd.

ASSISTANT: May I know your connection limit?

USER: I am looking for a connecting flight.

ASSISTANT: Do you have any other specification that you are looking for?

USER: Make sure that my return time must be evening.

ASSISTANT: May I know your name to proceed further?

USER: I am Ryan Clark.

ASSISTANT: I am sorry to inform you that there is no flight available at your request.

USER: Ok, not an issue. Anyways, thank you for the information.

ASSISTANT: Thank you for contacting us.