A. In general
Errors or omissions suffered in declarations already submitted that have led to the realization of a lower income than the one that would have legally corresponded or the realization of a return greater than the appropriate one, must be regularized by the presentation of a self-assessment complementary to the one originally presented.
Those unexpected situations or circumstances that cause the loss of the right to a reduction or exemption already applied in a previous declaration must also be regularized by submitting complementary self-assessments.
However, the loss of the right to certain deductions, as discussed in this same Chapter in the heading " Increase in liquid contributions, state and regional, due to loss of the right to deductions from previous years ", must be regularized in the self-assessment of the year in which the non-compliance with any of the requirements required for the consolidation of the right to said deductions occurred.
In accordance with the provisions of article 122.2 of Law 58/2003, of December 17, General Tax ( BOE of 18), a complementary self-assessment may also be submitted to request a lower refund to the self-assessed in the original declaration, in the event that the refund has not been made by the Tax Administration.
Complementary self-assessments, which may give rise to an amount to be deposited or an amount to be returned lower than that previously self-assessed in the event that the requested refund has not yet been made by the Tax Administration, must be made on the forms corresponding to the year that is the subject. of regularization.