Upgrade from openlitespeed to LiteSpeed Enterprise trial, you can backup your openlitespeed and remove the installation(if install through yum, just yum remove; If compile yourself, you can remove the installation folder, such as /usr/local/lsws, then install enterprise version and reconfigure the virtual hosts.
After trial expired, you can not use LSWS at more unless you purchase a license before the expiration. LSWS has a much more advanced feature.
Downgrade from LSWS to openlitespeed will be the simiar process, backup and remove /usr/local/lsws/ folder or uninstall through package manament such as yum remove. then install openlitespeed and reconfigure virtual hosts.
May we know do you have any particular reason to switch from OpenLiteSpeed to LiteSpeed Enterprise? Any particular feature you would like to use?