Running a private POA with clique. I know it is possible to add and remove signers using clique.propose().
However, If I lose access to one of the sealers defined in the genesis file is it possible to disable it and add one to replace it?
Genesis data is static. This information is used to init the blockchain and that's it. With clique.propose you can remove the genesis sealer later on. As long as your blockchain lives, the current set of sealers is what is counting, not what was in the genesis block. If your chain dies. E.g. all datadirs are deletes from all nodes, then you're starting with a blank chain anyway and you can init it with whatever genesis you like.