Some S is not in M.

Substitute for the Major Premiss its Converse by Contraposition, and for the Minor its Formal Obverse or Permutation, and you have FErIO of the First, with not-M as the Middle.

No not-M is in P.

Some S is in not-M,

Some S is not in P.

The processes might be indicated by the Mnemonic FAcsOcO, with c indicating the contraposition of the predicate term or Formal Obversion.

The reduction of BOkArdO,

Some M is not in P

All M is in S

Some S is not in P,