The ability to delete a person is on our product roadmap for a future release, but it has not yet been deployed.
Workaround - Re-use their profile and give to someone else you need to add to Metis. Alternatively, you can deactivate this person to stop them appearing on the People List (default view).
Didn't find what you need in this article? You can submit a support ticket or send an email to support@getmetis.com.