How to change rotation direction of 3-phase electrical machines?
The windings in a 3 phase motor, when activated by a 3 phase supply produce a rotating magnetic field in the rotor area of the motor. Swapping phase A with phase B re-orders the fluxes so that the flux rotates in the opposite direction. Swapping B with C does exactly the same thing as does swapping A with C. Think of it like a triangle with corners called A, B and C. If you swap any two corners and follow the points A, B and C you'll go in anopposite direction. Swap two more corners and you're back to the original rotation.

This is what it looks like. The black arrow is the flux produced by the three phase windings: -



Clearly, if yellow phase were swapped with blue phase the rotation would be opposite.