Before you upgrade to the full version, you need to save the changes you have made to the editor configuration (i.e. tools files, config files, etc.). After that you can retract and delete the Lite editor solution.
After you install and deploy the full featured version, you can copy your configuration files back in the editor folder. Finally, you will need to re-activate (deactivate and then activate) the RadEditor features on one site and recycle the SharePoint application. You only need to do this for one site - the editor will become active on all other sites after you restart the web application.
Unfortunately, it is not possible to have both the Lite and Full versions installed at the same time as they use the same solution and features IDs.
the Telerik team