It depends. if you reported Tax Exempt interest in Box 8 of the 1099 INT and Tax Exempt Dividends in Box 12 of the 1099 DIV, go back to those forms and remove entries in Box 8 and Box 12. Then add back the tax exempt interest in Box 1 of the 1099 INT and add back the tax exempt dividend in Box 1A of the 1099 DIV. This will now make both amounts taxable.
Why did you wish to reclassify these as taxable income?