In order to turn the camera 90 degrees so that you can perform push pull shots you can simply rotate the camera plate 90 degrees on your camera.
This may not always be practical, so another way to be able to change the orientation of your camera would be to mount a tripod head ontop of the Parallax. Since you are already utilizing our Kwik Release I would suggest our Low Profile Ball Head between the Parallax and the Kwik Release.:
If you wish to mount a flat mount style tripod head you would use our Flat Mount Adapter, for half ball mounted tripod heads our 100mm High Hat would need to be mounted ontop of the Parallax cart.