You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: I am Kimberly Hall from Washington. I want to change my existing reservation, due to my exams has been postponed. Can you help me to change it?

ASSISTANT: Sure, give me a minute.

USER: Sure.

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

USER: Ok, thanks for your information.

ASSISTANT: Thank you for opting us.