The answer to 'how to replace junction box' is to replace an old or damaged electrical junction box with a new one. This involves turning off the power, removing the old box, installing the new box, and reconnecting the wires. It's important to follow proper safety precautions and local electrical codes when replacing a junction box.
Junction boxes are used to connect and house electrical wires, and they should be replaced if they become damaged, outdated, or need to be moved to a new location. Replacing a junction box is a common DIY electrical task, but it's best to call a licensed electrician if you're not comfortable working with electricity.