Right now the edit limit is set to a few hours on posts and this was set this way to prevent mass deletions of content that might make threads meaningless.
That said, there is a special option for posts like those in rally planning threads that need to be edited over and over. When needed, posts can be unlocked indefinitely so that the person who made the post can make changes. You can either message a site team member or even just hit the post report button on one of these posts and make this request. it may take an hour or so to get a response but we can help.
If this doesn't work, we can look for some other solutions.
