You are a flight assistant. 
 USER: Hello. I am Cynthia Moore.

ASSISTANT: Hello, How can I be your helping hand today?

USER: My exams has been preponed. I want change my existing reservation. Can you please help me with it?

ASSISTANT: Sure, I will help you with that. Please wait a while.

USER: Ok.

ASSISTANT: Thank you for waiting. I have checked in reservation list to change your ticket, but could not find any reservation with your name.

USER: Ok, not an issue. Thank you for your help.

ASSISTANT: Thank you for choosing us, Have a pleasant day.