To propagate your Aglaonema 'Red Valentine': Be sure to wear gloves for this project since they can cause contact dermatitis or skin irritation from their sap. Water your plant the night before dividing. Inspect your plant for overcrowding. If they are root-bound in the pot, loosen the dirt around the root clump and brush away the soil. Begin to tease and pull apart the mass of roots. Ensure you have several healthy stalks and leaves attached to the clumps. Divide each clump into their pot, measuring 2 inches wider than the root mass and deep enough for its roots to grow. Plant in well draining potting mix amended with rooting hormone. Place the plant at the same level as the previous pot adding soil at the bottom. Water the soil and add more if settling occurs. Set them in medium, indirect sunlight. Check the moisture and humidity each day and add misting to keep the soil moist while the roots establish. After 6-8 weeks, roots will begin to develop. You can tug onto the stem to ensure the roots are anchoring well. Keep the air humid around it with a pebble tray and misting. Some die off of stems may occur from transplant shock. If this happens, cut the branches away and continue to hydrate, and keep the humidity level at a medium level while they recover.