[HowTo] change from OEM installation to normal user mode?

While installing Ubuntu 16.04 on my Laptop alongside Windows 10, I accidentally chose OEM install during the installation just to try what that option can do (without having any idea what it is). Later, I learned that OEM mode is a System Manufacturer Mode, and choosing this would allow one to customise the OS before shipping to the end-users. This is definitely not what I intended to do as a direct end-user. Therefore, I wanted to revert it to the normal user mode. The following is how I did in just 1 step.

— Double click on “Prepare for shipping to the end user” icon on the Desktop. Upon rebooting, you will be asked for your preference (including name and username), and voila! you can login as a normal from then on.