The following should work
Code:
Sub Macro1()
Dim oRng As Range
On Error GoTo lbl_Exit
Set oRng = ActiveDocument.Range
With oRng.Find
.Wrap = wdFindStop
Do While .Execute(FindText:="^13")
If Not oRng.ParagraphFormat.Alignment = wdAlignParagraphCenter Then
oRng.ParagraphFormat.Alignment = wdAlignParagraphJustify
End If
Loop
End With
lbl_Exit:
Exit Sub
err_Handler:
Err.Clear
GoTo lbl_Exit
End Sub