You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I am looking to book a flight ticket to meet my friend in Washington, can you help me for booking a flight ticket from OAK to DCA?

ASSISTANT: Sure, can you please share me with your dates of journey?

USER: My travelling dates are Aug 02 and Aug 04.

ASSISTANT: May I know your name please?

USER: My name is Joshua Moore.

ASSISTANT: Do you have any other specifications please?

USER: I need a single connecting flight.

ASSISTANT: May I know your airline preference please?

USER: My class preference is economy.

ASSISTANT: Please wait for a mean while.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry Moore, there is no flight found as per your travelling details.

USER: That's ok, thank you for checking.

ASSISTANT: You are welcome.