Section 40(3) in Tamil Nadu Government Servants (Conditions of Service) Act, 2016
(3)The transfer of a person from one class or category of a service to another class or category carrying the same scale of pay or pay band shall not be treated as first appointment to the latter for purpose of seniority and the seniority of a person so transferred shall be determined with reference to the rank in the class or category from which he was transferred; where any difficulty or doubt arises in applying this provision, seniority shall be determined by the appointing authority.