On a paper or exam last semester (I don't remember which), a student described someone who might "prepare for death by amending for their sins". My first guess as to the student's intent was that they meant "atoning for their sins". But why choose this word to confuse with "atoning"? I suspected maybe it had to do with making amends, something that seemed to me to be foreign to the idea of atonement, which (according to biblical teaching as I understand it) isn't accomplished by you. You don't atone for your sins. It's something that has to be done on your behalf, whereas making amends is something you do for someone else.
But this was probably a Roman Catholic student, probably raised with a simplistic understanding of what Catholicism teaches (given the bulk of the student body where I teach). Perhaps it's less strange to connect atonement with making amends if you think you earn your own atonement by doing good works, as I think a lot of nominal Catholics think their church teaches (it doesn't quite; at least, it's not as simple as that, because of the strong view of God's grace that stands behind any good work that God brings people to do). If you're thinking of working to repay God for your sins or something crazy like that, then you might think atoning is something like making amends to God for all the bad you've done. Someone of that mindset might easily confuse the two concepts.
But suppose you were to take this at face value. What would it even mean? I would understand grammatically what it would mean to amend your sins. You add something to them. I'm not sure if that would be good or bad, since it might be amending your sins by complicating them with further sins, or it could be amending your sins by removing some of the sinfulness. But amending for your sins? Amending what for your sins? Don't you need a direct object? It's at least grammatical to speak of amending an essay for my sins, but I'm not sure what it would even mean to amend for my sins without a direct object.