What is the process to go from Xfce to Gnome?
As a matter information and if relevant I am 12.1 upgraded and updated to max.
Thanks in advance
Go to into yast software management, you are probably using the gtk+ front end which I am not entirely familiar with. There should be a section for patterns in which you can select GNOME base system and GNOME Desktop Environment. Select at least the former and both if desired. Once it all is installed, you should be able to log out and select GNOME to have this desktop.
Back in Yast/Software Management/Pattens there is a section for xfce as well. As far as I know you cannot remove the pattern itself but you can select to remove all of the xfce software you do not want. It should clean up most libraries that are unused automatically.
Lastly I am not sure what display manager you are using. You can continue to use the one you are currently using with no problems. It might also actually be GDM from Gnome already (or otherwise it could be xdm or lightdm). If you are not using GDM and desire to change it,you can go into sysconfig settings in yast. Find the displaymanager key, and set it to use gdm. Then reboot to use the new display manager. Edit: Make sure the gdm display manager is actually installed first!