You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: My name is Michelle Campbell. I want to change my existing reservation due to postpone of my client meeting.

ASSISTANT: Sure. Wait for a while.

USER: Sure.

ASSISTANT: Thanks for waiting. There is no reservation found on your name.

USER: Not an issue, thank you for opting us.

ASSISTANT: Thanks for choosing us.