You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: There is a Baseball match between Denver team and san Francisco, so I want to book a ticket from SFO to DEN. My travel dates are 01/20 and return on 01/22.

ASSISTANT: Sure, may I know the dates of journey? Ok, wait a minute.

USER: Sure.

ASSISTANT: Sorry, there is no flight. May I know your name?

USER: My name is Brandon Hill.

ASSISTANT: Thank you.

USER: Thanks for your information.