Um. That I supposed.
Untrain is way more difficult than train, but faesible. In fact, that should not be too difficult if you find the "adecuate way" for her. (I solved a symilar issue in less then an hour, but she was a pup, I was much younger, and I do not think I'd do it the same way nowadays)
For her, it is not that bad. Given a good shelter outside she will be ok, but I assume you'd *like* her to come inside, plus it is good she does not have something to fear at home.
Best option would be getting a good trainer cause he would be able to gauge her reaction and find the best way for it.
Just as ideas. Take with a truckload of salt!!
- Try first differet buildings (industrial, big door, high ceilings, porch with two or three walls... whatever she accepts better and work from there.
- My first idea would be to walk her on the leash, head to the house FAST until she stops. Hold there, chill, try to have her seat or better lie down... sit at her side, wait whatever it takes for her to calm. Then continue the walk away from the house and repeat.
- You may also leash her at the comfort zone limit, leave some food a little bit further. (I do not like that so much because you are not involved here)
- I have seen this work too, if she has some good dog friends get them and try that the "guide her in" (even leashed). In group they are usually more daring