| Maezer |
No you can't retrain a prerequisite.
"You may change one feat to another through retraining. Retraining a feat takes 5 days with a character who has the feat you want. The old feat can’t be one you used as a prerequisite for a feat, class feature, archetype, prestige class, or other ability. If the old feat is a bonus feat granted by a class feature, you must replace it with a feat that you could choose using that class feature."
| Diachronos |
Even if you could retrain feats that are used as prerequisites, Snapping Turtle Clutch itself points out why retraining only Snapping Turtle Style wouldn't work:
While you are using the Snapping Turtle Style feat, the shield bonus the style grants to your AC applies to your CMD and touch AC. Whenever an opponent misses you with a melee attack while you are using the Snapping Turtle Style feat, you can use an immediate action to attempt a grapple combat maneuver against that opponent, but with a –2 penalty.[/qoute]