You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Cynthia Johnson.

ASSISTANT: How can I help you?

USER: I am planning to visit Downtown Aquarium at Washington, could you please help me with booking a flight ticket from OAK to DCA?

ASSISTANT: Sure, I will help you to book a flight ticket. Can you please share me your travelling dates?

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

ASSISTANT: Please give me a moment.

USER: I need a direct flight.

ASSISTANT: Sorry, no direct flights are available on your route.

USER: That's ok, not an issue. Anyways, thank you for the information.

ASSISTANT: Welcome, have a nice day.