The Form 1040X, Amended U.S. Individual Income Tax Return isn't accepted electronically; only an original tax return may be electronically filed. You must file Form 1040X on paper and mail it to the IRS. If you're due a refund, the IRS will issue you a check; a refund on an amended return can't be deposited directly to your bank account.
Can I file an amended Form 1040X electronically?