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, May I know your name?

USER: Jonathan Green here.

ASSISTANT: Please wait a second.

USER: Sure.

ASSISTANT: Sorry, No reservation found on your name.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for opting us.