Fill a bathtub or large plastic container with warm water. Place the rattan cane in the water and allow it to soak for 30 to 45 minutes. Alternately, wet large towels with hot water; lay the cane on top of a wet towel. Place a second wet towel over the top.
Pick up the cane and carefully bend it to test its flexibility. If the cane is not soft enough to bend easily, continue soaking it in the tub of water or letting it sit between the wet towels. Test the flexibility every 30 minutes until the cane is easily bendable.
Remove the cane from the water or from between the wet towels. Dry the cane with a towel so it is no longer dripping wet.
Position the cane on the furniture frame. Wrap the cane around the frame or weave it between other cane pieces. Hold the wet cane in place with caning wedges or place a rag over the cane and clamp it in place with hand-screw clamps. As the cane dries, it will harden and stay in shape.