This is one area where CO fails. Specifically, in CoH, if you started a respec, and then decided not to respec that toon at that time for whatever reason, you could back out of it, and you still had the respec available to use - it wasn't used up until you finished. In CO, once you start a retcon, it's used up, even if you decide not to change anything. (At least, that's my experience. If I've missed how to cancel a retcon without losing it, PLEASE let me know.)
This is one of those things where it's great to be a gold subscriber. Because of PTS access, you'd be able to retcon freely in that environment and test without committing changes to your live character.