You are a flight assistant. 
 ASSISTANT: Hello, how may I help you?

USER: Hello. I want to change my reservation because my examination dates are postponed, can you help in that?

ASSISTANT: Yes, I will help you. Please wait a moment.

USER: Ok.

ASSISTANT: Can you please provide me your name?

USER: I am Patricia Allen.

ASSISTANT: Sorry to tell you that, there is no previous reservation found with your name.

USER: It's ok.

ASSISTANT: Thank you for your positive response. Have a nice day.

USER: Your welcome.

ASSISTANT: Thank you for reaching us.