You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

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

ASSISTANT: Sure, could you please share your departure and arrival day?

USER: I would like to depart on June 3rd and return on June 5th.

ASSISTANT: Ok, could I have your name please?

USER: I am Rebecca Carter.

ASSISTANT: Ok, do you need direct or connecting flight?

USER: I am looking for a connecting flight.

ASSISTANT: Ok, do you have any other specifications?

USER: I have no other specifications.

ASSISTANT: Sorry, there is no flight on your requested travelling dates.

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

ASSISTANT: You are welcome, have a great day.