As per section 173 if you are re-appointing Mr. A, director after rotational retirement then it is an ordinary business to be passed by ordinary resolution. Form 32 not required to be filed bcoz there is no change in designation.
However if you are regularizing an additional director as a director then this is a special business to be passed by ordinary resolution bcoz it is change in designation. File Form 32 within 30 days of AGM.