Or without Copy.
Code:
Private Sub Worksheet_Change(ByVal Target As Range)
    
    If Target.Column = 7 And UCase(Target.Value) = "YES" Then
        Sheets("MESSAGE CHANGES").Cells(Rows.Count, 1).End(xlUp)(2).Resize(, 3) = Sheets("INITIATING DEVICES").Cells(Target.Row, 1).Resize(, 3).Value
    End If
    
End Sub