To add to what Erin said:
If Lucille is a living person with an e-mail address who you invited to join you on WikiTree, and she accepts the invite and creates a password, she becomes the manager of her own profile and can't be removed at the manager. You can be a second manager, but she has to be a manager.
There might be some ways to back into having you be the only manager, but our intent is to make sure a person always manages their own profile. We think this is important for privacy decisions.