Assessment work starts when a notice arrives — incomplete return, mismatch with 26AS / AIS, scrutiny, or a proposed variation. The reply has to answer the exact question asked, with papers the officer can verify, not a general explanation of the business.
Where the order is adverse, the next step is a rectification under section 154 or an appeal. We prepare the statement of facts, grounds, and paper-book, and appear or file written submissions as the forum requires. The same desk also handles lower-deduction certificates where the facts support an application.