You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you at this moment?

USER: Could you please change my existing reservation due to postpone of my board meeting?

ASSISTANT: Sure, please provide your name on which ticket is been booked.

USER: My name is Michelle Baker.

ASSISTANT: Sorry, there is no active reservation found on your name.

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

ASSISTANT: You are welcome, have a nice day.