You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Ronald Johnson.

ASSISTANT: How may 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 ready to help you. Please wait for a while.

USER: Sure.

ASSISTANT: Sorry Ronald, there are no reservation found on your name.

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

ASSISTANT: Thank you for opting us, have a great day.