Here's what I would do... Try her out in a pasture or somewhere outside but in a fence. Continue giving crisp clear instructions, so she has nothing to confuse. Start her back with basics walking, just simple things.

That is a good idea (riding her in a paddock). It really depends on if she improves, or if we just end up going backwards. In that case, she will be given to a friend of mine, and she won't be ridden. We can lunge her any speed, without her rearing, bucking, or anything.

Heres what I'm thinking, I would do what I suggested because I've used it a bunch and it knocks out rearing quite quickly, and then even if she goes backwards a bit, the rearing is gone and you can train her back up quite quickly.

How would one carry an egg around while riding a horse and waiting for it to rear?

Sooo glad one of you mods caught that comment. I was in total awe that someone would say that

Now I wanna see screenshots of that removed post...

(Dear god, how is an egg involved??? And if it involved hitting the horse on the head, then trust me that DOES NOT WORK AND WILL MAKE THE PROBLEM WORSE. Have you ever seen a horse rear with its head between its legs? Crazy isn't it, imagine how that started...)

But anyway, really good advice coming out of this thread (outside of the obvious exception). A horse that has begun to rear when they don't understand what is being asked of them/when they want to get out of work/when they are overwhelmed will never really stop. Its a learned behavior that unfortunately for us, is very effective in getting us to stop whatever it is we are doing to the horse. Groundwork is great, but Pandora's box has already been opened. Many trainers won't take known rearers (esp. if they have flipped) for this reason. There isn't a lot you can do to stop rearing except avoid the triggers and do your best to keep the horse focused on moving forward. Get the advice of a more experienced trainer, and if you are trying to sell, be honest and upfront. You don't want to be THAT trainer, and word will get around that you knowingly sold a dangerous horse under false pretenses. And I hate to float this option, but if the behavior cannot be managed then being PTS is the best option for everyone involved.

I removed it for a reason. We don't need drama.

Sorry to cause any drama with this topic I didn't realize people would post things like that. I meant that riding her in a paddock was good advice, not the other suggestion. I am going to a clinic and will be talking to a few professional trainers there :)