As per section 139(8) of the Companies Act, 2013 the Board of directors of the company shall have power to fill casual vacancy in the office of auditor within 30 days.
Procedure
1. Intimate the proposed auditor(s) regarding the intention of appointing him/it as auditor and ask whether he/ it is eligible and not disqualified to be appointed as auditor of the company.
Obtain consent & certificate from auditor.
2. If Audit Committee required to be constituted under section 177, then obtain its recommendation (Section 139(11)).
3. Call Board meeting.
4. Approve the appointment of auditor in casual vacancy at the Board meeting.
5. Intimate the Auditor and file with ROC form ADT-1 within 15 days.
No need to file ADT-2 as it is required to be filed in case of removal of existing auditor