My husband agreed to relinquish his rights to his children a few years ago but now knows it was a mistake. We live in NH and they live in AZ and are willing to move to AZ. Is there any chance of getting those rights back?
Once someone has terminated their parental rights voluntarily, it's pretty hard to restore them. However, I don't know that it is out of the question unless, say, there was an adoption outside the family. Otherwise, he may want to file for restoration of his parental rights. Moving to Arizona or at least a willingness to do so would go a long way toward showing depth of sincerity to be a part of his children's lives.
Best of luck, and let me know if I can help you further.