To manage system administrators, go to Yeeflow admin center, then expand Account setup and click System admins.
You can find the list with all the current System administrators on this page.
Click the "+ Add administrators" button from the right side. Then, from the pop-up window, you can add new users as the system admin, or remove users from the system admin list.
You can also click the remove button from the end of any current administrators to remove users from the admin list.
Note:
As the system administrator has the full control of Yeeflow, please ensure the user account need the privilege before your authorize it.