Only Admin have the permission to Deactivate Staff.
If they are an Admin, you must first "Remove as Admin", then you can deactivate them.
To Remove as Admin:
Go to Settings...go to Activated Staff List...Find the Staff, and if they are Admin, click on their name and then click "Remove as Admin"
To deactivate an Active Staff at your club:
Go to Settings, go to Activated Staff List. Find the Staff in the list and check the box next to their name. Then in the drop down box at the top of the list, select Deactivate Staff, then click GO.
This member will now appear in the Deactivated Staff List.