Sinking a die refers to producing the cavity that does the work.
Therefore, 'resinking' suggests that the cavity edges are worn out, the resulting product is out of spec, and the die block can be salvaged by removing material.
If, e.g., the die block had cracked, you would not have the resinking option, but would have to buy a new die block and sink a new cavity.
Mike Halloran
Pembroke Pines, FL, USA