In order to change the rotation of a three-phase motor, it is necessary to:

To change the rotation of a three-phase motor, swapping any two phases is indeed the correct method. In a three-phase motor, the direction of rotation is determined by the sequence of the phases. Each phase provides a magnetic field, and the order in which these fields interact dictates the direction the motor will turn.

When you swap any two phases, for instance, changing the connection of phase A with phase B, the sequence of the magnetic fields is altered. This effectively reverses the direction in which the magnetic field rotates, causing the motor to rotate in the opposite direction.

The other options do not achieve the same result. Increasing the voltage primarily affects the torque and speed characteristics but does not change the rotation direction. Adjusting the frequency can alter the speed of the motor but also doesn't change the direction unless phase sequences are changed. Reversing the current direction in isolation does not apply to a three-phase system, as current follows the established phase sequence determined by their connections. Thus, swapping any two phases is the proper method for changing the motor's rotation direction.