Procedure of replacing a root CA cert with another one of a different key pair in a fabric network?

Question

What is the procedure of replacing a root CA cert with another one of a different key pair.

Q-1 : Is that required to follow config update steps to do as we do in add/remove org, since RCA need to change?

(Understood that changing the RCA require to reCreate all peers,nodes, identities as well)

When we use the default setup of fabric CA, then

it bootstraps the fabric ca server with bootstrap administrator - 'fabric-ca-server start -b admin:adminpw -d'

On enrolling the bootstrap administrator -

It creates the following in msp : cacerts, Keystore, sign certs (Set-A)

now when we have to create identities then it uses Set-A, and all such stuff also got bind to the genesis block as well, as certificate got configured via ConfigTX file, and that got stored in the config channel of fabric.

Q-2 : Now If we have to change the RCA's cacerts, Keystore, sign certs (Set-B), then what is the procedure to do that ?

Not found any guidelines or documents on this, It's just logically understood if that is possible then maybe follow the similar steps as we do in add/remove orgs.

Q-3: But even to replace all identities with new RCA along with RCA's cert, key pair etc, then I don't think existing data may work?

if the live network already has x data, but RCA's cacerts, Keystore, sign certs and all identities got changed and also updated the config file with config-update way as we do in add/remove orgs so it has new certificate info ?