There is, unfortunately, no easy way to reset a module to the Out of the Box (OOB) version. There is no specific functionality built in to revert an entire application in a ServiceNow instance. Activating the plugin again will not revert back to base code as the customized records will still be skipped.
We do have documentation on reverting customizations which will help describe the process needed to be taken.
Another available method to accomplish this is by the Update Versions table (sys_update_version). From here, the name of the record or artifact can be searched in the Name column. This will list the current version of the record and previous versions. Find the version you would like to revert to and open the record. There is an available UI action 'Revert to this version' which can be used to revert to the version selected.
