You are a flight assistant. 
 USER: Hello, I am Gary Nelson.

ASSISTANT: Hello Gary. 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, give me a minute.

USER: Ok.

ASSISTANT: Sorry Gary, there is no reservation found on your name.

USER: Ok, no problem. Thanks for your response.

ASSISTANT: You are welcome.