You are a flight assistant. 
 USER: Hello, Raymond Williams here.

ASSISTANT: Hello, how can I help you at this moment?

USER: Can you please help me out in booking the ticket from DCA to OAK?

ASSISTANT: Sure, can you please share your trip dates to proceed further?

USER: Sure, my travel dates are 10/26 and 10/28.

ASSISTANT: Wait a moment please.

USER: Sure, I'll wait for your response.

ASSISTANT: Raymond Williams, there is no flight service available on this route on your provided dates.

USER: That's ok, thank you for giving the information.

ASSISTANT: Thank you for contacting us.