how to delete/remove calico cni from my kubernetes cluster

I have installed my kubernetes cluster(1master, 3worker)in the digital ocean.
The problem is I installed both flannel and calico in this cluster.
I want to remove the calico completely from my cluster or is it ok to have multiple CNI?

Why Calico is needed in Kubernetes?

Calico enables Kubernetes workloads and non-Kubernetes or legacy workloads to communicate seamlessly and securely. Kubernetes pods are first class citizens on your network and able to communicate with any other workload on your network.

What is calico and flannel in Kubernetes?

Flannel is an overlay network mechanism where as Calico is basically a pure L3 play. Flannel works by using a vxlan device in conjunction with a software switch like linux bridge or ovs. Container A when tries to reach container B on different host the traffic is pushed to the bridge on host A via the VETH pair.

Use following two commands to remove calico from your node:

kubectl delete -f https://docs.projectcalico.org/v3.3/getting-started/kubernetes/installation/hosted/rbac-kdd.yaml
kubectl delete -f https://docs.projectcalico.org/v3.3/getting-started/kubernetes/installation/hosted/kubernetes-datastore/calico-networking/1.7/calico.yaml