RACE to POOP.

Every letter change

1. RACE → LACE: change letter 1 from R to L.
2. LACE → LACK: change letter 4 from E to K.
3. LACK → LOCK: change letter 2 from A to O.
4. LOCK → LOOK: change letter 3 from C to O.
5. LOOK → LOOP: change letter 4 from K to P.
6. LOOP → POOP: change letter 1 from L to P.