You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you? May I.

USER: I am Susan Lopez, want to travel from OAK to DEN.

ASSISTANT: May I know your travelling dates?

USER: My travelling dates are from 06/22 to 06/24.

ASSISTANT: Sorry, there is no flight available as per your request.

USER: That's fine, thank you.

ASSISTANT: Most welcome.