If you are presently using the free version of the plugin and need to upgrade to the Pro version for whatever reason, the procedure is fairly simple. Please install the plugin by following the steps that have been provided here, and then deactivate the Permalink Manager Lite plugin. It is not necessary to keep both plugins enabled.
The procedure is absolutely risk-free, and none of your data, including any custom permalinks or settings, will be lost at any point throughout the migration process.