If you are using a Noram Premier Stinger or Noram GE ultimate, you just change the driver and reuse the old drum. If you are using the Noram GE, the above is correct. On the GE, the driver and drum is all one part.
^ There you go.
The Stinger is a decent clutch and popular with the L206 racers. It uses Bully style drivers right out of the box.
I suspect from how the OP posed his question, it just may regard the L206 and current clutch rules.