While editing a referenced drawing or a block definition in place, you can save back or discard changes.
While editing a block reference in place, you either can save back or discard changes made to the reference. If you save back changes to a reference, the drawing is regenerated.
When the changes are saved back, the block definition is redefined and all instances of the block are regenerated to reflect the changes. If you choose to discard the changes, the working set is deleted and the block reference returns to its original state.
Similarly, while editing an xref in place, you can save back or discard changes. Objects in the working set that inherit properties not originally defined in the xref retain those new properties. For example, an xref contains layers A, B, and C, and the drawing that references it contains layer D. If new objects are drawn on layer D during in-place reference editing and changes are saved back to the reference, layer D is copied to the xref drawing.
If you remove objects from the working set and save changes, the objects are removed from the reference and added to the current drawing. Any changes you make to objects in the current drawing (not in the xref or block) are not discarded. If you delete any object that is not in the working set, the object is not restored even if you choose to discard changes. You can return the drawing to its original state by using UNDO. If you make unwanted changes to an xref and use REFCLOSE to save back the changes, you must use UNDO to undo any changes made during the reference editing session. After you have undone any unwanted changes, use REFCLOSE to save changes to restore the xref file to its original state.
Objects in the current drawing that inherit properties defined by the xref retain those new properties. Properties taken from the xref drawing are bound to the current drawing. The xref layer named SITE, for example, appears in the current drawing as $#$SITE when assigned to an object not in the working set. If BINDTYPE is set to 0, a prefix of $#$ is added to the reference name in the current drawing. If BINDTYPE is set to 1, reference names remain unchanged in the current drawing, similar to names of inserted objects.