If you already mailed the amended return, or e-filed it and it was accepted, you can't undo it. Just wait until the dust settles, and don't do anything more. You will probably get the refund from the IRS recalculation of your tax return before they process the amended return. Eventually you will get a letter from the IRS telling you what they did with the amended return. That could take 6 months or more. Hopefully they will just ignore the amended return. After you get the letter you'll see if you have to take any further action.
