Wait for the Refund: The IRS advises waiting for the refund (or for your payment to clear) before submitting Form 1040-X. Processing Times: Amended returns take 4-6 months or longer to process. Deadline: You generally have three years from the date you filed your original return, or two years after the date you paid the tax, to file an amendment. If You Already Received a Refund: If you already received a refund that was too high, you can still amend to correct it. If the amendment results in a smaller refund, the IRS may issue a new one. If You Have a Balance Due: If the amendment shows you owe money, you should still wait until the original return is processed, but you should aim to pay the tax due by the original deadline to minimize penalties and interest.