Undo will remove all edits made to a MARC 21 bibliographic record. For example, if you add or delete a field or modify data in an existing field and use Undo, then all of the changes you made will no longer appear in the record.
You cannot cancel any changes that were made before you saved or validated the record.
Note: If you are a WMS library or using full WorldShare Record Manager, please see Undo a change to a MARC 21 record.