Detaches objects and modifiers (and combinations) logically from the driver node of which they're instances or references.
Go to the object or modifier level in the stack for an instanced or referenced object or modifier (respectively), and click Make Unique.
For instanced object/modifier combinations, in the modifier stack, choose either the modifier or the object itself.
When you click Make Unique for a selection of two or more objects, a dialog appears that asks: Do you want to make the selected items unique with respect to each other? This gives you a choice of how you want to make the objects unique.