For the people who are going to visit this thread later, what I found works is basically providing all the defining parameters of the clearml worker and then passing the arg --stop in the command.
Ex: sudo clearml-agent daemon --detached --queue gpu_default gpu_priority --gpus 0 --docker --stop
What didn't work for me: sudo clearml-agent daemon --stop <worker-id>

@<1523701087100473344:profile|SuccessfulKoala55> I have also tried using the API reference listed None to unregister a worker. However, it goes unregistered for a few seconds and comes back up on the UI. The Post request returns with a 200 response and says that the job is done.

SlimyElephant79 when you change the clearml.conf file used by an agent, you'll need to stop the agent and run it again

@<1523701087100473344:profile|SuccessfulKoala55> What would be the recommended command to delete/unregister an agent? None of the CLI commands seemed relevant to this operation other than the clearml-agent daemon --stop command that seems to only be stopping running instances of the agent and not unregistering it.

Hey @<1523701087100473344:profile|SuccessfulKoala55> that was actually my first approach. I used the command clearml-agent daemon --stop <worker-id>
However, this is what I saw: