You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, How can I serve you today?

USER: I am Elizabeth Evans. I want to change my reservation due to my exams has been preponed.

ASSISTANT: Sure, Wait a minute. I will check and let you know.

USER: Ok.

ASSISTANT: Thank you for waiting. There is no recent reservation found on your name.

USER: Thank you.

ASSISTANT: Thank you for approaching us, Have a great day.