You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I want to change my existing reservation as my plan to participate in basket ball match at Denver has been cancelled. Can you help me with that?

ASSISTANT: Sure, I will help you with that. May I know your good name?

USER: Thank you. Sure, Michael Williams here.

ASSISTANT: Please wait for a moment.

USER: Sure.

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

USER: Ok, no worries at all. Thank you for your kind service.

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