Based on your example document:
Code:
Sub ChangeParasAfterHeading()
Dim para As Paragraph, nextPara As Paragraph
Dim oRng As Range
Dim i As Integer
If Selection.Type = wdSelectionIP Then
MsgBox Prompt:="You have not selected any text!"
Exit Sub
End If
Set oRng = Selection.Range
With oRng
For Each para In oRng.Paragraphs
For i = 1 To 7
If para.Style Like "Heading " & i & "*" Then
Set nextPara = para.Next
If Not nextPara Is Nothing Then
If nextPara.Style = "Body Text" Then
nextPara.Style = "Body" & i
End If
End If
End If
Next i
Next para
End With
lbl_Exit:
Set oPara = Nothing
Set nextPara = Nothing
Set oRng = Nothing
Exit Sub
End Sub