There is a tool included with EPDM called Rollback. This allows an administrator the option to delete current and previous versions to restore a file to an older version. There is no control how far back the rollback allows a person to go so be careful who you give this to! GXSC recommends only the build in administrator account be allowed the rollback option. A person could rollback a released file to version 1, when it was an empty file. It is best used as a tool to test new system changes on particular files, rolling back files as they go through states and transitions until the process works correctly.
Remember, be careful! Those later versions will be gone forever!
If the file you are rolling back is referenced you will get an error about that as well.
There is however a safe method to do a rollback, one that does not delete versions. Any user can do this, granted they can "get" earlier versions. To do this, check out the file and 'get' the earlier version:
Afterwards continue with the rest of your design process. The next time it is approved to be released it will be the most recent revision, and not revision A or B. In this case the next revision will be C.