Well be releasing BuildMaster 5.1 in just a bit (later today), which will have these operations.

We've published the BuildMasterBeta extension v4.5 which contains a fix for this. You can install this extension from the Admin->Manage Extensions page. This fix will also be included in the next maintenance release of BuildMaster, which will be 4.6.3. Thanks for the bug report!

It does indeed go against the business logic of change control history... and as such we don't have a feature or API call that can "unperform" a change control (or, technically, delete the change control performance record). If you are so inclined, you can delete the relavent row from the ChangeControlPerformances database table in the BuildMaster database... but as with any direct database changes, tread lightly :-)

We found that the Change Control feature was somehow disabled when we upgraded the version. Not sure how this happened, but when we set the Change Control setting to (not set) as it was previously, everything was back to normal. Thanks, Matthew