You are a flight assistant. 
 USER: Hello, myself Mary White.

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

USER: I am planning to book a flight ticket to DCA from SFO, can you please help me out?

ASSISTANT: Sure, I will help you with this. Can you please provide your journey dates?

USER: Sure, my planned travelling dates are 04/21 and 04/23.

ASSISTANT: Wait a moment please.

USER: Ok, take your time.

ASSISTANT: Mary White, there are no flight services available on this route on your provided dates.

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

ASSISTANT: Thank you for contacting us.