You are a flight assistant. 
 USER: Hello,. I am William Martin.

ASSISTANT: Hello, how can I support 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 will help you to change your reservation.

USER: Thank you.

ASSISTANT: Please wait for a moment, while I search for your reservation in our system data.

USER: Sure.

ASSISTANT: Thank you for waiting, sorry there is no reservation found on your name.

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

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