The command is simply:
npm uninstall <name>
A local install will be in the node_modules/ directory of your application. This won't affect the application if a module remains there with no references to it.
If you're removing a global package, however, any applications referencing it will crash.
Here are different options:
npm uninstall <name> removes the module from node_modules but does not update package.json
npm uninstall <name> --save also removes it from dependenciesin package.json
npm uninstall <name> --save-dev also removes it from devDependencies in package.json
npm uninstall -g <name> --save also removes it globally
Hope it helps!!