[Digital Jedi]

If you change the replacement text of a Smiley in the Smileys Manager, the old text will not work anymore, and all that will show in old posts is the text. If you don't want that, you can just upload the Smiley under a different file name, and use different text for it. However, the old Smiley will still show in the Smileys List whenever it's opened. You can push it down to the bottom or to another category, if you like.

You could also try using something like Word Replacement to always change the old :lol: to the new text.