Income tax assessment procedure

Dear all,

I have a query regarding IT assessment procedure :- Mr. X, an ITO called for information u/s 133 (6) from an assessee, issued notice u/s 148. Thereafter without issuing notice u/s 143 (2), initiated aasessment proceedings. While the assessment was pending, he got transferred & one Mr. Y who has been transferred in his place issued notice u/s 142 (1) & 143 (2) directly i.e. without issuing notice u/s 148. What is the validity of such notice u/s 142 (1) & 143 (2)?
I.e whether notice u/s 143 (2) issued by subsequent AO can ratify the act of earlier AO who started assessment proceedings without issuing notice u/s 143 (2) ?

Thanks in advance.