ODF Regional-DR : OCP clusters have overlapping networks - How to change CIDR of these ?

Issue

We installed ACM on an OCP Cluster "A" and imported other two clusters "P" and "S" that represent the Primary "P" and Disaster Recovery "S" Clusters.

The three cluster have the same network address config as below, you can check that on each cluster with the following command:

# oc get networks.config.openshift.io cluster -o json | jq .spec
{
  "clusterNetwork": [
    {
      "cidr": "10.128.0.0/14",
      "hostPrefix": 23
    }
  ],
  "externalIP": {
    "policy": {}
  },
  "networkType": "OpenShiftSDN",
  "serviceNetwork": [
    "172.30.0.0/16"
  ]
}

The ODF documentation says that "The managed clusters must have non-overlapping networks" (referring to the Primary and Secondary cluster "P" and "S")
ODF 4.12 - 4.3. Requirements for enabling Regional-DR

Q1. Does this requirement apply also to the cluster "A" (the one where ACM is installed) ?
Q2. How do we change this CIDRs for cluster/service networks with one of the managed clusters ?