This discussion concerns a Customs Examiner who resigned technically from Chennai to join Mumbai Customs in the same role and grade pay. The core questions revolve around whether seniority benefits can be carried over to the new post in Mumbai and if the previous appointment qualifies as a substantive post under DOPT rules. Guidance suggests that while pay is protected, seniority is generally not retained unless specific service rules permit, though the option to return to the parent department within a lien period might allow seniority recovery.