Separate
Obtain the individual parts that were used to create a union.
A union could consist of several parts of which some could also be unions themselves. The separate tool, in a sense, copies out all the parts that were used to make the last union. If the separated (copied out) parts are unions themselves, then the tool can be run again to separate those parts as well.
Note:
When a union that contains a transform is separated the transform is deleted and the entities revert back to the state prior to being unioned.