You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello. How can I assist you?

USER: I am Nicholas Walker. I want to book a flight ticket to visit Thomas Jefferson Memorial in Washington, DC - IAD. Can you please aid me in booking a flight ticket from Oakland?

ASSISTANT: Ok, may I know your travelling dates?

USER: I wish to board on 05/30 and intend to return on 06/01.

ASSISTANT: Please mention our source airport code?

USER: My origin airport code is CA - OAK.

ASSISTANT: Sorry, no flight found on your route.

USER: Ok, not an issue. Thanks for the help.

ASSISTANT: Thank you for reaching us.