You will need a blunt object that will fit through the non drive side of the hub, Something like a thin rod of metal,a socket extension or a large wooden dowel. You want to push the spring plate onto the drive and driven rings and bearings. Tap around the edge of the spring plate in a circular motion slowly to remove the bearing carefully. If your going to stretch it dont over do it and deform it, A few centimeters will be fine. Use a few blocks of wood and a G clamp to press the bearings back in.