Revision or rectification of return AY 2019-20

Suresh G S (43 Points)

19 December 2020  
Due to discrepancies in Demat holding for AY 2019-20 the sale of shares shows a small LTCG. However, on correction of the discrepant holdings and recalculation of CG, shows a capital loss.
in order to carry forward the loss to the current AY 2020-21, can the previous return be revised now?
If not, is there any other solution?
Please clarify.