Individual income tax returns from 2009 and forward may be amended electronically through Revenue Online (state website) . Filing and amending returns in Revenue Online is a free service. You may amend online even if the original return was filed on paper. Revenue Online has all the information from your original return. You will not need to re-enter everything.
• If you cannot amend online, you may file the DR 0104X.
Make sure you use the appropriate form version for the year you are amending.
• If you are changing your Colorado return because the IRS made changes to your federal return, you must file the DR 0104X within 30 days of being notified by the IRS. You must amend your Colorado return in this case, even if there is no net change to your tax liability.
IT IS VERY IMPORTANT THAT YOU SUBMIT ALL SCHEDULES AND SUPPORTING DOCUMENTATION FOR ANY CHANGES WITH YOUR AMENDED RETURN. YOU MUST SUBMIT ALL SCHEDULES, EVEN IF YOU ARE NOT CHANGING THOSE VALUES