You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I serve you?

USER: Can you help me in booking my flight ticket from OAK to DEN?

ASSISTANT: Sure.

USER: Thank you.

ASSISTANT: When would you like to make your journey?

USER: My trip dates will be Sep 6th to Sep 8th.

ASSISTANT: Can I know your name?

USER: I am Sharon Phillips.

ASSISTANT: Is there any other requirement?

USER: I need a business class flight.

ASSISTANT: Ok. We are unable to provide flight in between your journey routes due to some technical up-gradation at destination airport.

USER: Its ok, thank you.

ASSISTANT: Thank you for choosing us.