If you'd like a colleague or a friend to have access to and be able to edit your SleekBoxes, you can add their email address under Add super user.
Go to 'Account', then 'Users.
Note: The email address you enter, must be an email address that is registered with us. Simply use the desired email address to sign up for a trial. It is, of course not necessary to have a pricing plan on a super-user account