You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER:  I need to change my existing reservation as my exams got postponed, Can you please help me with that?

ASSISTANT: Sure, I am happy to help you. Can I have your good name?

USER: Anna Smith here.

ASSISTANT: Sorry, there is no active reservation on your name in our records.

USER: No issue, thanks for the information.

ASSISTANT: Thank you for choosing us.