There’s only one SpectraLayers 7 installer for both editions (Pro/Elements). So no need to uninstall/reinstall, it only depends on what licenses are active on your dongle.
If you have purchased an Elements license, and you add a Pro trial to your dongle, as long as the Pro trial is valid (so during 30 days) SpectraLayers 7 will launch as “Pro”. Once your Pro trial is no longer valid, SpectraLayers 7 will launch as “Elements” again.
No worries if you worked with a Pro license and are back to an Element license, your projects will still be compatible (both in standalone mode and ARA mode).