Because the center of lift would jump from the 25% point from one leading edge to the 25% point from the NEW leading edge at the point of reversal you had better believe that the CG would have to move, and move a LOT. It would be worse than you think too since the CG position for what would suddenly be a canard would need to be closer to the new leading edge or even in front of the new leading edge. So some way to slide the main wing back and forth or some way to shift a lot of the heavy components and alter the CG that way is a must. At the same time the old vertical would have to snap into hiding and the new vertical(s) snap out and into place. Ideally this would be done at a low airspeed or right at the stall point otherwise the new configuration would be like flying an arrow backwards all of a sudden. Just think of a standard model noseing up into a stall and then BAM! the fin on the tail snaps into hiding and the wingtips snap up and back to form new fins while the innards run backwards on rails inside the fuselage to move the CG from the 35% mark from the new trailing edge to some point just in front of the new leading edge so you have a suddenly functional canard form.

You could actually jig all this up with a little all balsa test glider in a few minutes and see how much it would have to move.