Use a SEQ field for the chapter numbers then if you change the orrder again you can update the field to change the numbers e.g.
Code:
Sub Makro7()
Dim oRng As Range
Dim oFound As Range
Set oRng = ActiveDocument.Range
With oRng.Find
Do While .Execute(FindText:="Chapter")
Set oFound = oRng
oRng.Collapse 0
oRng.Fields.Add oRng, wdFieldSequence, "ChapterNum", False
oRng.InsertBefore Chr(32)
oFound.End = oRng.End
oFound.Style = "Heading 1"
oRng.Collapse 0
Loop
End With
End Sub