Locking cells out with macro

Hi guys,

I'm trying to set up a macro that locks or unlocks a column depending on what is put in the column before it.

at the moment i've got the code written in the worksheet

Const pwd = "Flowerpot123"
Private Sub Worksheet_Change(ByVal Target As Range)

If Target.Count > 1 Or Intersect(Target, Range("AD14:AD38")) Is Nothing Then Exit Sub
With Target
    .Parent.Unprotect pwd
    .Offset(, 1).Resize(, 2).Locked = UCase(.Value) = "APPROVAL REQUIRED"
    .Parent.Protect pwd

End With
End Sub

However, this means that the cells are unlocked if the cells AD14:AD38 are blank. How do I make it so that they are ONLY unlocked when the word "Approved" is in the AD column?

Thanks!