You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you out?

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

ASSISTANT: Sure, I will help you in booking the ticket. May I know your travelling dates please?

USER: I would like to take off on 10/05 and return on 10/07.

ASSISTANT: Sorry, there are no flights found in our database.

USER: That's ok, I will find an another alternate way to complete my trip. Anyways, thank you for the information.

ASSISTANT: Thank you for choosing us.