You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you today?

USER: I am Margaret Robinson, I need to change my existing reservation due to postpone of my exams. Could you please help me?

ASSISTANT: Sure, we are glad to help you. Let me check the reservation status and get back to you.

USER: Sure.

ASSISTANT: Sorry, we could not find your reservation in our booking list.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for choosing us.