There is no limit to revise the Tax audit reports.But it can be revised only to meet some technical requirements. (i) revision of accounts of a company after its adoption in annual general meeting.
(ii) change of law e.g., retrospective amendment.
(iii) change in interpretation, e.g. CBDT’s circular, judgments, etc.
(iv)Any other reason like system/software error requiring change in report already uploaded.