If you can't edit an employee's role, you don't have permission to change the settings. You'll need to reach out to someone in your company who has a higher role than you.
It is not uncommon for a manager/owner of a large brand to be unable to edit one of their employees' roles. This is likely because the employee also teaches/works at another studio. When this happens, you'll see an error message indicating that "You do not have permission...".
For example, if you are a Manager/Owner of Studio A, and you have an employee who works/teaches at both Studio A and Studio B, you are unable to edit that employee because you don't have permission at Studio B.
In this case, you will need to reach out to your company's HQ to resolve this.