I think the easiest way is to redeploy agents to your computers but you won't need to check it again in your repository because if it's working as it should be the agent in your repository will be automatically encoded with your new epo server settings
when you have populated the directory with placeholders ( through an imported list of machines, or AD or whatever).....
make sure when you send out the agent install you check to force install and UNCHECK the only install on computers that do not have an agent.
this is the equiv of the /forceinstall switch for the agent install and will install over the old version.
*make sure you have rights *switch off the macfee access protection rules that stop mcafee processes from being stopped as these may stop the new agent install (you can put them back once you have migrtaed)