currently kubeadm command provides a command join to join a cluster. but there isn't a command to leave that cluster. maybe kubeadm leave is suitable for this circumstance

kubeadm version

version.Info{Major:"1", Minor:"5+", GitVersion:"v1.5.0-alpha.0.1534+cf7301f16c0363-dirty", GitCommit:"cf7301f16c036363c4fdcb5d4d0c867720214598", GitTreeState:"dirty", BuildDate:"2016-09-27T18:10:39Z", GoVersion:"go1.6.3", Compiler:"gc", Platform:"linux/amd64"}