Sub Macro1()
Dim oFld As Field
    For Each oFld In ActiveDocument.Fields
        If oFld.Type = wdFieldSequence Then
            If InStr(1, oFld.Code, "Appendix") > 0 Then
                oFld.Result.InsertAfter ")"
                oFld.Result.InsertBefore "("
            End If
        End If
    Next oFld
    Set oFld = Nothing
End Sub