Hi,
It depends very much on how your player is builded. if it's only a matter of switchin mesh, then you can access it directly using "set property" action, or simply drag the mesh component directly onto the playmaker state action editor tab. then you'll be able to switch mesh.
else, I would recommand you simply have prefabs, and load/parent the one you need to your player. Your player being an abstract entity that simply waits for it's "body".
Does that help?
bye,
Jean