In the External References palette, in the File References pane, select the underlay you want to detach.
Right-click on the underlay and click Detach.
The underlay is no longer linked to the drawing file. All instances of the underlay are removed from the drawing.
Note
Erasing an individual instance of an underlay is not the same as detaching it. An underlay must be detached to remove the link from your drawing to the file.
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