renaming nodes

I have a 4-node cluster in my homelab. I want to rename two nodes, and also delete a third node (originally created for quorum purposes only). What is the best way to proceed? I could migrate all VMs and CTs to the one node that won't be renamed, remove all the others, rename two of the nodes...

Minor problem: I may have mismanaged renaming a new PV server. To upgrade an existing PV host to PV 5.2 I had our network folks assign a new physical computer a temporary name in our campus DNS, then ran a clean PVE 5 install on it. I copied over my VM snapshot files, unpacked and ran one...