Tax Audit Report cannot be revised under normal circumstances. However in the following circumstances it can be revised:
Revision of accounts of a company after its adoption in the AGM.
Change in law with retrospective effect
Change in interpretation of law (CBDT Circular, Notifications, and Judgements etc.)
Any other reason like system/software error requiring change in report already uploaded.
There is no limit to revise the Tax audit reports. The only suggestion from the guidance notes and the department is that it should be in a way suggested in SA- 560.
In case of revision of a Tax Audit report, the auditor shall state that it is a revised report and shall also state the reason for the revision.