Add label to self-hosted runner via command

I have been trying to add a custom label to our self-hosted runner using the command shown in the docs ./ --labels mylabel but whenever I use the command I get an error "Cannot configure the runner because it is already configured. To reconfigure the runner, run 'config.cmd remove' or './ remove' first." From what I understood in the docs I should be able to add a label to the runner when it is already in place so this makes me think I’m encountering a bug. Is there something I’m missing from the docs to add a custom label?

Note: I saw some questions with a similar error that were trying to add an additional runner to the same host. I am not trying to do that, we’ve got one runner per host and I just need to add a custom label to that runner without being disruptive and having to remove/reconfigure it.

Sadly, it appears ./ is designed for either starting or stopping a runner and not changing an existing runner. And when you start a runner, you can specify the labels you want it to have.

You can instead use the normal github api (or gui) to add additional labels to your existing runner: