You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Brandon Roberts from Oakland.

ASSISTANT: How may I guide you?

USER: My friend has invited to attend an event at Denver. Can you help me in booking a ticket from OAK to DEN?

ASSISTANT: Please help me with your travelling dates.

USER: I have a plan to travel on dates 10/25 and 10/27.

ASSISTANT: Please hold on a moment.

USER: Sure.

ASSISTANT: Brandon, no flights has been found on your journey dates.

USER: Its ok, thank you for the information.

ASSISTANT: Thank you for choosing us.