You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Edward Campbell.

ASSISTANT: How can I help you today?

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

ASSISTANT: Sure, please mention your travel dates.

USER: I would like to depart on Apr 25th and return on Apr 27th.

ASSISTANT: Do you have any connection limit?

USER: Yes, I need a connecting flight.

ASSISTANT: May I know your depart and return time?

USER: I have to return in the morning.

ASSISTANT: Can you have any other specifications?

USER: No.

ASSISTANT: Sorry to inform this, no flights are found on your desired route.

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

ASSISTANT: Thank you for opting us.