According to the permissions set by the Admins in the Admin CP here on LS1Tech, you have 1 year (525600 minutes) to adjust the thread title and have it apply to the forum display listing. There are two parts to editing the thread title. One having it apply to the thread title while viewing the actual thread, and the other having it apply to the thread title while viewing the actual thread AND the forum display. It is the forum display that has a 1 year time limit, per Admin CP.
I see the thread you are likely speaking of (you entered 9/6 in the title instead of 4/6), and you should be able to fix that on your own as it's a thread you created within the past year.
Therefore, as suggested, go to the post, click on the Edit button and then click on the Go Advanced button to edit the thread title.