Currently, it's not possible to remove collaborators from a Studio prototype.
To remove collaborators from a prototype:
Sign in to InVision and open your prototype.
Beneath the prototype name, click the People tab.
Next to a collaborator, click the ••• (more) menu, and then click Remove.
Confirm by clicking Yes, remove them.
You can also remove collaborators via the prototype Share button or the Add / Remove people button on the People page. When the modal opens, click Remove next to the collaborator(s). Confirm by clicking Save changes.