A. In general

Errors or omissions in declarations already filed that have led to a payment being made less than that which was legally due or a refund that is higher than that which was due, must be settled by filing a self-assessment that is complementary to the one originally filed.

Additionally, additional self-assessments must be made available, situations or circumstances that result in the loss of the right to a reduction or exemption already applied in a previous declaration.

However, the loss of the right to certain deductions, as mentioned in this same Chapter in the heading "Increase settlement of the state and autonomous payments, due to the loss of the right to deductions from previous years , "must be settled in the self-assessment of the financial year in which any of the requirements for the consolidation of the right to these deductions have been breached.

In accordance with the provisions of article 122,2 of the LGT, a supplementary self-assessment may also be filed to request a refund lower than the self-settlement in the original tax return, in the event that the refund has not been made by the Tax Administration.

With regard to the LGT, see Act 58/2003, of 17 December, General Tax (Official State Gazette of 18 December).

Supplementary self-assessments, which may result in an amount to be paid or an amount to be returned less than the amount previously settled in the event if the requested refund has not yet been made by the Tax Administration, it must be made in the forms corresponding to the financial year that is subject to regularisation.