Suppose that a user has down voted an answer to a question that they didn't completely understand. Years later, they read the answer again and find it to be good, but cannot change their vote because the answer has never been edited. Is it OK to make a minor grammar improvement for the purpose of reversing the old vote and upvoting the answer?
6$\begingroup$ I'd advise letting bygones be bygones. One mistaken downvote isn't going to harm anybody. Also, read Shog9's excellent answer here, which explains the motivation behind vote-locking. $\endgroup$– user199113Feb 12, 2019 at 21:59
When you try to change your vote on a post, you get a message like "You last voted on this post on [timestamp]. Your vote is now locked in unless the post is edited." The time window during which votes can be retracted is very brief, like five minutes.
The intended use case for the feature is if you've voted on a post and an edit later changes the post in a way that changes your opinion of it. For example, maybe an answer has a serious flaw, so you downvote and leave a comment explaining why. The author of the post changes it so that it no longer has the problem that bothered you. In that case, changing a vote would make sense.
If your opinion on a post changes even though the post does not, there's an argument to be made for finding a way to improve the post yourself --- a spelling fix or a grammar improvement --- so that you can change your vote on the edited post. However, the edit needs to stand on its own its own merits. Users who have earned the privilege of un-reviewed edits are reminded in the guidance that "tiny or trivial edits are discouraged"; lower-reputation users, whose edits are still subject to review, are discouraged from making tiny edits by a kind-of-dumb algorithm. The dumb algorithm is not hard to circumvent, but we discourage "harmless" hacks whose purpose is to avoid a software limitation.
For that matter, you could consider the tactic of "make a minor edit to allow a vote to be changed" --- that is, the subject of your question --- as a "hack" to get around the software limitation on changing votes. That's the kind of thing that might be okay if it happened once, or rarely; however, if you find yourself frequently running up against software restrictions that prevent you from doing something, it's worth asking whether the thing you're unable to do is really consistent with the way that we hope people will use our site.
In the specific case linked in a previous version of this question, a user with a history of trouble with trivial edits proposed a trivial edit to an old post, and left a comment suggesting they were about to embark upon a program of such edits and vote changes. A series of trivial edits would be much more disruptive than a set of old mis-cast votes, and so the proposal drew a somewhat harsh response from a moderator. (That moderator was me. I try not to write harshly, but I miss the mark sometimes. Sorry.) Hopefully this answer supplies a little more nuance.
$\begingroup$ The author of the post changes it so that it no longer has the problem that bothered you. In that case, changing a vote would make sense. Sadly there are some who still don't change their downvote even after corrections :( $\endgroup$ Feb 15, 2019 at 0:52
$\begingroup$ @KyleKanos well, you don't get pinged when a post you downvoted has been edited. $\endgroup$– RuslanFeb 23, 2020 at 11:48