You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you today?

USER: Could you please book a ticket with a direct flight?

ASSISTANT: Sure, please let me know your planned travelling dates.

USER: I have planned to travel on Dec 29 and return on Dec 31.

ASSISTANT: Is there any other specifications?

USER: No.

ASSISTANT: May I know your name please?

USER: My name is Patrick Davis.

ASSISTANT: Kindly share your boarding and landing airport codes.

USER: I am heading to OAK from DTW.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

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

USER: Not a problem, thank you for the information.

ASSISTANT: Thank you for availing us.