You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: Myself Gregory Turner. I want to change an existing reservation, please help out.

ASSISTANT: Sure, I can help you in that one. Please wait for a while to check your status.

USER: Ok, take your time.

ASSISTANT: I have checked as per your request in our previous list but I am unable to find your ticket booking in our list to modify it.

USER: Its ok, no problem. Thank you for your information on my request.

ASSISTANT: You are welcome and have a nice day.