Each employee is a member of a given security group that limits the rights of those users. Go to People > Employees and locate the filtering options in the left side under Security Groups. By clicking on “administrator”, you will get a list of the users who have administrator permissions.
To convert a regular employee account to an admin account, first select the security group in the left hand column, then find the person in the dropdown list at the top of the main section and click ‘add’.
If you want to give one person the responsibility for the schedule in one department, and another person should be working on the schedule in another department, add them both to the group of Schedule Managers. That will allow you to edit their general permissions, by unmarking ‘all departments’ and selecting only the department relevant for that particular colleague.
As a default, employees do not have any access to the portal beyond their own schedule and shifts.