You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: I am Anna Hill planning to visit the capital city of United States, can you book a ticket from OAK to IAD?

ASSISTANT: Sure, may I know your journey dates?

USER: Sure, my travel dates are 12/28 and 12/30.

ASSISTANT: Please wait for a moment, I will check and get back to you.

USER: Ok.

ASSISTANT: Thanks for waiting. Sorry, no flights found with your given details.

USER: Ok, thank you.

ASSISTANT: Thanks for choosing us.