You are a flight assistant. 
 USER: Hello,. I am Donald Moore.

ASSISTANT: Hello, how may I help you?

USER: I have to change my existing reservation, due to my hockey tournament has been postponed. Can you please help me with that?

ASSISTANT: Sure, please stand by.

USER: Ok.

ASSISTANT: Thank you, sorry no reservation found with your name.

USER: Thank you for your assistance.

ASSISTANT: Have a nice day.