Instructions
Make sure that your pistol is unloaded. If you are just handling your pistol to determine and change the EER, then there's no need for a pistol to be loaded.
Aim your pistol at a target to get a feel for the current distance of eye relief. When you observe your target at the eye relief distance, you should have a complete sight picture. The lowest amount of eye relief is at the highest magnification setting.
Increase your extended eye relief by reducing the magnification setting on your scope. When your scope is set to the lowest magnification, the extended eye relief is at its maximum distance.