Sub aaa()
  Dim aFN As Footnote, aRng As Range, aRngRef As Range, sCode As String, aFld As Field
  Set aRng = Selection.Range.Sections(1).Range
  With aRng.Find
    .ClearFormatting
    .Text = ""
    .Style = "MyStyle"
    Do While .Execute
      sCode = "TC """ & aRng.Text & """ \l 1 "
      aRng.Collapse wdCollapseEnd
      Set aFld = ActiveDocument.Fields.Add(Range:=aRng, Text:=sCode)
      aFld.Select
      Selection.Font.Reset
      aRng.Start = Selection.Range.End
      aRng.End = aRng.Sections(1).Range.End
    Loop
  End With
End Sub