ALTER TABLE Departments
ALTER COLUMN ManagerId INT NULL

SELECT EmployeeID
FROM Employees AS e
INNER JOIN Departments AS d
ON E.DepartmentID = D.DepartmentID
WHERE D.Name IN ('Production', 'Production Control')

DELETE FROM EmployeesProjects
WHERE EmployeeID IN
        (
            SELECT EmployeeID FROM Employees AS e
            INNER JOIN Departments AS d
            ON E.DepartmentID = D.DepartmentID
            WHERE D.Name IN ('Production', 'Production Control')
        )

UPDATE Employees
SET ManagerID = NULL
WHERE ManagerID IN
        (
            SELECT EmployeeID FROM Employees AS e
            INNER JOIN Departments AS d
            ON E.DepartmentID = D.DepartmentID
            WHERE D.Name IN ('Production', 'Production Control')
        )

UPDATE Departments
SET ManagerID = NULL
WHERE ManagerID IN
        (
            SELECT EmployeeID FROM Employees AS e
            INNER JOIN Departments AS d
            ON E.DepartmentID = D.DepartmentID
            WHERE D.Name IN ('Production', 'Production Control')
        )

DELETE FROM Employees
WHERE EmployeeID IN
        (
            SELECT EmployeeID FROM Employees AS e
            INNER JOIN Departments AS d
            ON E.DepartmentID = D.DepartmentID
            WHERE D.Name IN ('Production', 'Production Control')
        )

DELETE FROM Departments
WHERE Name IN ('Production', 'Production Control')