Sub Demo()
Application.ScreenUpdating = False
With ActiveDocument.Range
  With .Find
    .ClearFormatting
    .Replacement.ClearFormatting
    .Text = "^13[!A-Za-z0-9~] "
    .Replacement.Text = "^p"
    .Forward = True
    .Wrap = wdFindStop
    .Format = False
    .MatchWildcards = True
    .Execute Replace:=wdReplaceAll
  End With
End With
Application.ScreenUpdating = True
End Sub