In some situations, you may want to "declone" or "free a clone" (i.e., change it to a "normal" element). You can do this by right-clicking on the clone you wish to declone in the graphics pane or a browser to access its context menu, and selecting Free Clone.
In either case, the element will be changed into a "normal" element: it will no longer be a clone (and the Clone tab will no longer appear in the properties dialog for the element).
Note that if the element was one of only two clones before it was freed, the other remaining clone would also be automatically freed (since it would have no other clones).
Similarly, if you delete a clone which was one of only two clones before it was deleted, the remaining clone is automatically freed.