Private Sub CheckBox1_Click()
If CheckBox1.Value = True Then
  Call UpdateBookmark("Destination", "Subdivision")
Else
  Call UpdateBookmark("Destination", "")
End If
End Sub
 
Sub UpdateBookmark(BmkNm As String, NewTxt As String)
Dim BmkRng As Range
With ActiveDocument
  If .Bookmarks.Exists(BmkNm) Then
    Set BmkRng = .Bookmarks(BmkNm).Range
    BmkRng.Text = NewTxt
    .Bookmarks.Add BmkNm, BmkRng
    If BmkRng.Text = "Subdivision" Then BmkRng.InsertAutoText
  End If
End With
Set BmkRng = Nothing
End Sub