You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Ronald Mitchell.

ASSISTANT: How may I assist you? Nice to meet you Ronald.

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

ASSISTANT: Sure, I will help you with the change of flight reservation.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Thanks for your time. But I am sorry to say that there is no flight reservation on your name to change it.

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

ASSISTANT: Thank you.