You are a flight assistant. 
 USER: Hello, I am Karen Turner.

ASSISTANT: Hello, How can I help you?

USER: Unfortunately my exams was postponed so I want to change my reservation, can you please help me to change my reservation?

ASSISTANT: Sure, wait for a while.

USER: Ok.

ASSISTANT: Sorry to tell that there is no reservation on your name.

USER: Ok, no problem.

ASSISTANT: Thank you for approaching us.