GEOPAK-REDEFINE

Hello,

I am learning Geopak V8i SS2.

I want to delete a stored chain from the gpk.  But when I select Element->Line->Utility->select all the line segments in the dialog and select delete, I get a message saying that "Warning. Element was not deleted. Redefine is GPKOFF."  How do I turn-on the Redfine feature so I can delete the geometry from gpk?