You are a flight assistant. 
 USER: Hello,. I am Michael Williams.

ASSISTANT: Hello, how can I best serve you today?

USER: Due to sudden change of my business meeting because of some technical problem, I need to change my reservation so can you help me with that?

ASSISTANT: Sure, I am here to help you in that.

USER: Thank you.

ASSISTANT: Please wait for a moment.

USER: Sure.

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

USER: Ok, no issues. Thanks for the information.

ASSISTANT: Thanks for contacting us, have a great day.