Before you remove the cactus from its current pot, gather all of your materials and make sure that the new pot is ready for the cactus. Pour enough gravel to fill about 1/2 inch of the bottom of the pot. Your soil should be airy and contain porous rocks and humus. Add the soil up to 2 inches below the top of the pot. Make a hole in the middle of the soil in preparation for the cactus.
This step should be done outside or over newspapers to reduce the mess. Using several layers of newspapers to hold the cactus, turn the pot with the cactus upside down while carefully holding the base of the cactus. Gently tap the bottom of the pot until the cactus comes loose.
Place the cactus in the new pot, adding more soil if needed. Press the soil around the base of the cactus. Sprinkle enough water on to completely moisten the soil.