You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you?

USER: Will you please help me in booking a flight ticket from DEN to OAK?

ASSISTANT: Sure, We are here to help you. May I know your travelling dates?

USER: My travelling dates are Oct 20th and Oct 22nd.

ASSISTANT: Do you need any break?

USER: Yes, I need a break.

ASSISTANT: Can I know your name?

USER: Angela Phillips.

ASSISTANT: Is there any other specifications?

USER: The return time should be evening.

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

USER: Ok, thank you.

ASSISTANT: Thank you for reaching us.