Polarization rotation of field-induced phase transformations was observed by means of a polarizing microscope on a (001)-cut single crystal Pb(Mg1/3Nb2/3)(0.76)Ti0.24O3 (PMNT24%) at room temperature with an electric field applied along the [001] direction. A hysteresis loop was also measured for comparison. As the electric field increases, polarizations of rhombohedral R domains rotate toward the [001] tetragonal T-001 phase through M-A-type monoclinic distortions, i.e., R-->M-A-->T-001. The crystal cannot entirely reach the T-001 phase as the field approaches 44 kV/cm. In addition, spotlike domains that perhaps correspond to M-B-type monoclinic or triclinic phases were also observed. This field-induced phase transformation is strongly irreversible.