Can she get this error in her reaffirmation corrected?

No, it cannot be undone.

Not to my knowledge. This response is based on the very limited information provided here.

If the problem were a mutual error on a reaffirmation agreement, it could be likely reformulated through a stipulation of the parties. However, it appears she wants to back out of her agreement entirely. This is very hard to do and perhaps impossible. She might want to contact the lawyer, who presumably was told she did want to reaffirm, and see if he can reopen the whole thing, or find some other way to correct what might be his mistake. He will likely say he remembers explaining it all to her before she signed which might or might not be true. In any event, it's best to start with the lawyer. But don't be optimistic. Good Luck.

Did the reaffirmation agreement get accepted by the judge? Merely signing a reaf doesn't make it effective. The judge has to approve it. If it was approved by the judge, there is scant hope that she'll be able to reopen the case 6 years later.

It would sort of depend on whether this reaffirmation was submitted to the bankruptcy court and approved by the judge. Why not take a look at the court records? If approved by the judge, it is carved in stone. BTW, is there some reason your daughter did not ask this question herself? If she is going to sign legal papers as a grown up, Mom probably ought to be letting her act like a grown up and stop making excuses for her. Attorneys do not generally coerce people into signing reaffirmation agreements on mortgages. My experience is that people scream at their attorney to give them reaffirmation agreements to sign. Then when something goes wrong, the blame is placed on everyone but the person who wanted to keep the property regardless of the repercussions.

No. Unfortunately, your daughter cannot change her mind with regards to her mortgage at this point. She would be responsible for any deficiency balance if the mortgage were to foreclose.