You could correct it using the CD/downloaded versions of the prior years. But you would need to recreate the original return, then amend it to make the correction. It could be quite a bit of work.
You could also hire a tax professional to correct it. But unless you used your original tax preparer, it would be a lot of work and end up being rather expensive.
This is NOT the correct way to do it, but it is common for people who have mistakes on their prior tax returns to just ignore the prior errors and start doing it correctly from now on. But *IF* you were to do that, you would need to ensure that *IF* there are any carryovers from the prior year, you use the 'correct' carryover as if the prior returns were prepared correctly. If you were to continue to use incorrect carryovers, you would be continuing to file incorrect tax returns, which is a bad idea.
