You are a flight assistant. 
 USER: Hi, I am Edward White.

ASSISTANT: Hello, How can I serve you?

USER: As my plan to attend exam but due to some problems my exams got post pone.

ASSISTANT: Ok.

USER: Can you help me in change an existing reservation?

ASSISTANT: Sure. Wait a minute.

USER: Ok.

ASSISTANT: Thanks for waiting. There is no reservation found on your name.

USER: Ok, no problem.

ASSISTANT: Thanks for choosing us.

USER: Thanks for your information.