How to switch ubuntu to any ubuntu based without installing fresh copy of operating system

 
I really like this trick because you can switch any of ubuntu distros(gnome, kubuntu, xbuntu, edubuntu,lubuntu)desktop environment without installing a fresh copy of operating system but can keep maximum two operating system desktop environment.it's like you installed a transformation pack in windows platform. Without wasting my and I am come to how you can do it
For gnome(Ubuntu)

GNOME is a user-friendly desktop environment that enables users to easily use and configure their computers. GNOME includes a panel (for starting applications and displaying status), a desktop (where data and applications can be placed), a set of standard desktop tools and applications, and a set of conventions that make it easy for applications to cooperate and be consistent with each other.
Open terminal type this command sudo apt -get install gnome-desktop "and press enter than press y after finish logout to see the change
Kubuntu

kubuntu is kde's plasma desktop kubuntu is really good desktop and its start Manu is easy to navigate it start Manu has four categories application, system kubuntu is a fast flexible operating system when you install kubuntu package it will give some kubuntu software
Run this command for kubuntu desktop
sudo apt -get install kubuntu-desktop
And wait for few second when terminal ask yes or no press y for yes and press enter after it downloading and installing package logout re log in
Xubuntu
Xubuntu is an elegant and easy-to-use operating system. Xubuntu comes with Xfce, which is a stable, light and configurable desktop environment.

Xubuntu is perfect for those who want the most out of their desktops, laptops and notebooks with a modern look and enough features for efficient, daily usage. It works well on older hardware too.
Go to command line interface (terminal, kansol) and type this
sudo apt -get install xubuntu-desktop
Than press y and press enter reclogging to see the change

Edubuntu

The Edubuntu project aims to maintain high quality educational and related packages in Ubuntu. Basically edubuntu has great look and developed for student but you can use it for normal use
How to switch
Open your terminal (command line interface) and type this command
sudo apt -get edubuntu-desktop
Wait few second when prompt y/n press y to confirm, it will download and install Edubuntu packages log out and reclogging to see the change
I hope you like this post if any confusion leaves your comment into comment box
Important: sometime this error type of error comes see the following image

It error come because you misspell operating system name correct the name and rerun these command