delete an Xref with a red (!)

How can I eliminate an Xref with a red exclamation mark next to it ? I'm kind of a neat freak and want to clean up my xref manager workspace.

Detach it.

Ohh, that's what detach does.

Thanks. I was afraid detach was far more serious

Straight from help.

You can detach an xref definition to remove the xrefs completely from your drawing. You can also erase the individual xref instances. Detaching the xref definition removes all dependent symbols associated with that xref. If all the instances of an xref are erased from the drawing, AutoCAD removes the xref definition the next time the drawing is opened.