The easiest route would be if you have shell/command line access and are able to stop node-RED uninstall node-red-contrib-home-assistant and then install node-red-contrib-home-assistant-websocket
# stop node-red $ cd ~/.node-red $ npm uninstall node-red-contrib-home-assistant $ npm install node-red-contrib-home-assistant-websocket # then restart node-red
If that’s not an option you could export all the flows that use the Home Assistant nodes save them in a text file so you accidentally don’t lose them. Then delete the flows you exported which should then allow you to uninstall node-red-contrib-home-assistant via the palette and then install node-red-contrib-home-assistant-websocket. After that, you should be able to import the flows that you exported earlier. Using this method you’ll probably have to re-enter your Home Assistant credentials.
@frenck posted on Reddit instruction if you’re a hass.io user. https://www.reddit.com/r/homeassistant/comments/9gb5vr/looking_for_some_nodered_testers/e66or5b/