For 2011, I filed "single" instead of "HOH" by mistake. My itemized deductions were $24,000. Should I file a 1040 X to change my status?
You can file for form 1040X since it was a mistake made when preparing the tax return and not a math error. It is normally referred to as an amended tax return, which should be filed upon realization. Read more on http://taxes.about.com/b/2007/04/22/how-to-correct-mistakes-on-a-tax-return.htm.