Yes, on both interior and exterior doors, just the slab can be replaced. However, we do caution that a new slab is only as good as the frame you put it into. Therefore if a frame is out of square or rotting, we recommend replacing the complete unit. Additionally, many vendors stock doors with the hinges already routed, and it may or may not line up with the existing door frames. Standard sizes also vary between manufacturers. A door without hinge or bore prep is recommended, and the ability prep in the field is necessary. When requesting Slab pricing, you will need the actual slab dimensions in inches, not just a call size like 3/0 x 6/8.