You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I be at your assistance?

USER: My name is Michael Carter and I want to change my reservation, can you please help me?

ASSISTANT: Sure, please be on hold.

USER: Ok, take your time.

ASSISTANT: Thank you for your time. Sorry, there is no reservation matching with your name in our portal to make changes further.

USER: Ok, thank you for the information.

ASSISTANT: Thank you for opting us. Hope to serve you the best next time.