Only the Admin of the project has the ability to manage members. Any project member can delete themselves unless the Admin has changed the add/remove permissions. If you are an Admin and want to delete someone from the Independent project, simply hover over their icon in members section and choose Delete icon:
Note: Admin permissions settings are only available in premium Independent Projects and premium Team Projects. To see all the benefits of upgrading your Independent Project or Team to Premium, click here.
This will prompt a window asking whether you are sure you want to delete the member:
Click "OK" to delete the Member.