You can rename the titles of your own discussions any time after you publish them. You might do this, for example, if you realize afterward that your title is not as relevant, clear, or concise as it could be.
To edit the title, click the down arrow at right of the Reply button in the right side of the screen (desktop), then Rename.
This will give you a popup field to edit the discussion title. Click OK when done.
The title is presentation only, not part of the thread’s permanent link. Changing the title will not break any bookmarks that might have been made to the discussion. The true discussion URL is dependent on the discussion’s ID number alone. For example, this post’s URL appears to be thevidme.club/d/155-edit-rename-a-discussion-title, taking into account the current title. But the real permanent link is only the part up to the ID number: thevidme.club/d/155.
Also see adding Links about relative and absolute paths to discussion board content.