You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

USER: Can you help me to book flight ticket from DEN to DCA?

ASSISTANT: Sure, may I know your planned travel dates?

USER: My planned dates are Aug 28 and Aug 30.

ASSISTANT: May I know your connection limit?

USER: I prefer a connecting flight.

ASSISTANT: Do you have any other specifications?

USER: I need a normal cost airline to travel.

ASSISTANT: Your good name please.

USER: David Clark here.

ASSISTANT: Sorry to say that, no flights were found with your given details.

USER: Ok, not a problem. Thank you.

ASSISTANT: Thank you for reaching us.