If they have been in 12/12 for awhile, double potting will be your best bet and cause the least amount of stress. Cut the bottom out of the current pot, and put the entire plant and cut pot into another, same size pot about 1/2 full of soil. This way there will be no x-plant stress and should keep growing without a pause

If you can't do that and you HAVE to X-plant, be as gentle as possible and try not to damage the delicate roots, and then water it in good with plain water (not food/water) give it a couple of days, and then continue on your normal schedule. It'll porobably stunt it for a few days til it gets used to the new container