Remove a User from a SharePoint Group from Site Settings:
- Navigate to the site where the group will be used.
- On the site’s home page select Site Settings from the “Site Actions” menu.
- On the Site Settings page in the Users and Permissions sections click on the People and groups link.
- Select the group from which user(s) will be removed.
- Click on the user(s) to be removed.
- Click on the down arrow next to the Actions option to open the menu.
- Select Remove Users from Group on the Actions menu.
- On the dialog confirmation prompt click OK to confirm the action.