Any Reformer Library that you purchase or make yourself can be edited and used in your DAW, just like regular libraries. When you use the Reformer Pro plugin, the software will access these files and run its processing.
The advantage of purchasing a Reformer-compatible version of a sound library is that you can ALSO perform the library using the software, greatly expanding the use of the content.
NB! Removing or altering the original audio files used in the Reformer Library is NOT recommended. This may cause issues with the plugin, and make the Reformer-compatible functionality unusable.