Add formula if adjacent cell has name in it but remove formula in adjacent cell is blank

[How How]

Hi,
I'm close to what I need but my problem is although I've ammended this code to enter the Rand() formula if a name is entered in the adjacent cell. But it's not removing the formula if I remove the name from col A (I'm building a random draw so the amount of names can change).
can anyone help please?

Name col A3:A35

Formula Col B3:B35

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
     
    Dim B As Range
     
    Application.ScreenUpdating = False
     
    For Each B In Range("B3:B35")
        If Intersect(ActiveCell, Range("A3:A35")) Is Nothing Then
            Exit Sub 'active cell is not in the range of input cells
        Else
            If B.Offset(0, -1) <> vbNullString Then
                B.Value = "=Rand()"
        Else
        
            End If
        End If
         
    Next B
     
    Application.ScreenUpdating = True
     
End Sub