To re-initialize a swarm in Docker, use the command 'docker swarm init --force-new-cluster' which creates a fresh cluster without reconnecting to old nodes.
To re-initialize a Docker swarm so that it does not attempt to reconnect to old nodes, you should use the command docker swarm init --force-new-cluster. This will create a new swarm cluster and prevent the Docker daemon from attempting to connect to any previous nodes that were part of the old swarm. The command docker swarm leave --force is used when you want to remove a node from the swarm, but it does not create a new cluster. The options docker swarm init --force and docker swarm reset --force are not valid commands in Docker.