How to edit topic slug?
I'm sorry but there is no way to edit topic URL (slug). The only workaround is using phpMyAdmin Database Management tool in your Hosting Service cPanel. Using this tool, you can find the topic row in wp_wpforo_topics table and change the slug field value. Then Navigate to WordPress Dashboard > Forums > Dashboard admin page and click on [Delete all caches] button.
In case you want to say thank you !)
We'd really appreciate and be thankful if you leave a good review on plugin page. This is the best way to say thank you to this project and support team.