You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I  help you?

USER: I want to change my existing reservation, due to my exams has been postponed. Can you please assist me to change it?

ASSISTANT: Sure, may I know your name please?

USER: My name is Kimberly Turner.

ASSISTANT: I am sorry no reservation found on your name.

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

ASSISTANT: Thank you for choosing us.