If you electronically file a tax return that has already been filed and accepted in paper form, your submission will receive this reject:
Reject Code: R0000-933-02
If "Amended Return" or (Superseded for 1120/1120S/1120-F/1041/1042/1065) checkbox is not checked, then taxpayer TIN in the Return Header must not be the same as a TIN of a previously accepted paper return for the return type and tax period indicated in the tax return.
If you intended to file an amended or superseding return, you should indicate that in the return and resubmit it. Otherwise, the return has already been filed.