To use each character's special Dresspheres, you must activate all the Dresspheres on your Result Plate (all lines in the plate should be glowing in blue). If activated, the "R1 Special Dress Change" message will flash. To change, press R1 and Action. The only difference is that the Special Dressphere will control the other character, and the character using the special Dressphere will be the only one who will receive the experience.