Digital Ah! It may depend on the permissions the admins assign the users. Here on flarum.org I can edit my posts, not the thread title, and nothing else. I have just tested on a freshly installed forum, and you indeed can alter your own thread title and delete it, with the admins being able to limit it or not.
Changing one's own thread tags is possible, but by default the setting is set on a weird "Custom" that does not allow it.
However, one cannot flag their own post.
