I figured out which one you were talking about and changed it for you. Like said above, use the triangle report post icon and just tell us what you want. There are enough of us on that we should have it fixed up for you without significant wait.

It isn't a key in the DB. But the software restricts editing a thread title to mods/admins only. You can change a POST title, but not a thread title.

I think they did this in the software to avoid frequent title changes which would make it hard for members to check back in or follow up on an interesting post they had previously read or responded to.