Press R3 (when Form is unlocked). Press R3 + Down button to revert.

Sometimes there are different types of transformations for a character. For example, Gohan can turn Super Saiyan into Great Saiyaman. Press the D-pad to transform into another type of form. In other cases pressing different directions can skip transformations. For example, Goku turning into Super Saiyan 2 without turning Super Saiyan first. Note: For one level of transformation you need one Favorite gauge bar.