You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how can I amend you?

USER: I am Kenneth Lopez. I want to change my existing reservation due to my exams got postponed. Can you please help me?

ASSISTANT: Sure, I will help you.

USER: Ok.

ASSISTANT: Please stand by.

USER: Sure.

ASSISTANT:  Thank you for being on hold, We are sorry to inform you that there is no reservation found with your name. Thanks for your approach.

USER: Thanks for your response.