In your organization you may have decided that only the Loops administrator for your organization has the right to remove participants from Loops. In that case you go to her/him for help. If you have the right to do it yourself, you do it in the settings of your organization. Click the symbol for your organization and Participants. In the list of participants you click the name of a specific person and then you choose to Delete her/him if that is what you wish to do. Click the trash can or “Delete participant”.