Comment 85 for bug 130325

It depends how you install it.

Install Method A: adding his repo to your sources.list
1. You can add the ppa to your sources.list (bit overkill)
2. Update to that xserver using update-manager

Remove Method A:
1. type sudo nano /etc/apt/sources.list
2. delete the line containing his ppa-repo
3. Control+O to save
4. type aptitude update
5. type aptitude clear
6. type aptitude reinstall xserver-xorg
7. DONE

If you just directly install the .deb file with gdebi you can remove it by starting at point 4.
You don't need to remove the repo in that case, just clear the cache!

You can also likely do something like:
sudo aptitude install xserver-xorg/gutsy

You can also just launch aptitude and do in the text-gui of aptitude (which is much like synaptic)
You should be able to revert to another version there.