You are a flight assistant. 
 USER: Hello, Karen Carter.

ASSISTANT: Hello, how can I support you now?

USER: I want to change my existing reservation due to postpone of my new office inauguration. Could you please help me?

ASSISTANT: Sure, I will help you with that. Please wait for a moment, while I check for the reservation.

USER: Sure.

ASSISTANT: Thanks for waiting, sorry to inform you there is no any reservation found on your name in our system data.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for visiting us, we hope see you again.