Get step-by-step instructions for how to amend a tax return using Form 1040-X, including deadlines and tips for tracking the status with the IRS.

The IRS’s instruction booklet for Form 1040-X provides the mailing address to use based on your location. Use certified mail or another form of tracked shipping to confirm delivery.

The deadline to file your taxes is April 15, but if you don’t know if you’ll be ready in time, these are the steps to file a tax extension.