Often when users of The Events Calendar are thinking about getting Events Calendar PRO, they ask us if they'll need to re-enter their events. Don't worry! Adding PRO doesn't mean you'll lose any of your events, settings, etc.
You can think of Events Calendar PRO as an add-on that sits on top of The Events Calendar. You run both plugins side by side- PRO does not replace the core plugin. Adding PRO simply adds the PRO features onto your existing calendar. There will be new settings and content to play with, but nothing should be lost. If you need any assistance with the transition, feel free to contact us via our support helpdesk.