Revised return and interest as per 234(a)

For the last assessment year 2017-18, After receiving notice under 143(1)(a) - due to variance in income as a mismatch with 26AS, If I need to pay additional tax by filing revised return - then under which section  the revised returned will be filed ? Also Do I need to pay interest under section 234(A) on the additional tax that need to be paid,  considering original return was filed timely ?