If your plant is rootbound, you'll need to carefully untangle the roots before replanting. Here's how:
1. Gently remove the plant from its pot. Be careful not to damage the roots.
2. Loosen the root ball with your fingers or a small tool. Be careful not to break any roots.
3. replant the plant in a larger pot with fresh soil. Water well and keep an eye on it for signs of stress (drooping leaves, etc.).