You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: My name is Brenda Rodriguez. I would like to travel from DEN to OAK, could you help me out?

ASSISTANT: May I know your desired travel dates please?

USER: My preferable dates are from 11/02 to 11/04.

ASSISTANT: Sorry to say, there is no flight on your desired travel dates.

USER: That's ok. Thank you for your help.

ASSISTANT: Thank you.