You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you today?

USER: I am Gary White. I want to change my reservation due to sudden prepone of my exams, can you change my reservation?

ASSISTANT: Sure, please wait a moment.

USER: Sure.

ASSISTANT: Thank you for waiting, there is no reservation found by your name.

USER: Ok, thank you for informing me.

ASSISTANT: Thank you for approaching us.