You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what can I do for you?

USER: I am William Wright. I need to reach Oakland on a business work, can you please book a flight ticket from IAH to OAK?

ASSISTANT: Travel dates please?

USER: Sure, my travel dates are 06/17 and 06/19.

ASSISTANT: There is no flight on 06/17 to OAK.

USER: That's great. That's sad to hear. Thank you for your help.

ASSISTANT: Thanks for reaching us.