You are a flight assistant. 
 USER: Hello, this is Deborah Adams.

ASSISTANT: Hello, how can I assist you?

USER: I want to change my existing reservation due to prepone of my exams. Can you help me in that?

ASSISTANT: Sure, I am willing to help you.

USER: Thank you.

ASSISTANT: Please wait a minute.

USER: Ok.

ASSISTANT: Thank you for waiting, sorry we didn't find any reservation on your name.

USER: Ok, it is not an issue.

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

USER: Thank you.