Section 112(6) in The Central Goods and Services Tax Act, 2017
(6)The Appellate Tribunal may admit an appeal within three months after the expiry of the period referred to in sub-section (1), or permit the filing of a memorandum of cross-objections within forty-five days after the expiry of the period referred to in sub-section (5) if it is satisfied that there was sufficient cause for not presenting it within that period.
