If you save or discard changes with REFCLOSE, you can still use the UNDO command
to return to the reference editing session. If you have made unwanted changes to an
xref and already saved back the changes, use UNDO to undo the unwanted changes; then
use REFCLOSE to save back changes and restore the xref to its original state.

The following prompts are displayed.

Save

Saves back to the xref source drawing or to the block definition in the current drawing
all changes made to objects in the working set. If you remove an object from the working
set and save changes, the object is deleted from the reference and added to the current
drawing. The Save Back Changes to Reference button on the Refedit toolbar automatically
saves reference editing changes.

NOTE: If the file format of the xref source drawing is AutoCAD Release 14 or earlier, the
file is saved in the drawing file format of the current release. The file format is
not changed for xref source drawings in AutoCAD 2000 or more recent formats.

Discard Reference Changes

Discards the working set; the source drawing or block definition is returned to its
original state. 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. The Discard
Changes to Reference button on the Refedit toolbar automatically discards reference
editing changes without using REFCLOSE.