You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you?

USER: I am Daniel Robinson. Can you help me in booking from DCA to OAK?

ASSISTANT: Sure, may I know your travel dates please?

USER: My travelling dates are 01/23 to 01/25.

ASSISTANT: Sorry, there is no flight available on your requested dates.

USER: No issue, thank you.

ASSISTANT: Thank you for approaching us.