You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I am Jonathan Robinson. Can you please change the existing reservation due to abnormal weather condition from DCA to OAK?

ASSISTANT: Sure, we are perky to help you. Please wait for a while.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on your name in our database.

USER: No problem, thank you for your information.

ASSISTANT: Thank you for choosing us.