Comment 3 for bug 48777

Hmm... there are two issues here, as I see it.

One - reconfiguring xserver-xorg after a "bad" or suboptimal configuration. It would seem this is what the original reporter had in mind - for reference about Xorg configuration/auto-configuration issues, please see the (closed) bug 11155 and the followup at https://launchpad.net/distros/ubuntu/+spec/xorg-config-ui .

Two - if xorg is correctly configured, changing the used resolution. As mentioned by Rich, in this case there is a GUI (either via System Settings, or right-click-on-desktop -> "Configure Desktop).

An additional option is running "krandrtray", which stands for"KDE Resize and Rotate System Tray App", and which resides thereafter in your system tray. (On Breezy, at least, no menu entry for this is included, so you have to start it from the command line.)