Amended Returns If any changes made to your federal return affect your state income tax liability, you are required to report the change to the Delaware Division of Revenue within ninety (90) days after the final determination of such a change and indicate your agreement with the determination or the grounds of your disagreement. Use Form 200-01-X to change an income tax return you have already filed, and attach a copy of any federal adjustments.
All amended returns must be printed and mailed with necessary attachments.
