The new employer/management, in my opinion, can continue compliance under the ESI Act, 1948, and the rules/regulations framed thereunder on the old Code Number allotted to it. However, in case of past liabilities, kindly see Section 93A of the said Act.
In case of a change of name of the unit/factory also, in my opinion, the same old code number can continue.
However, in order to avoid any doubt at the level of authorities, it is essential and important that the new employer/management informs the Branch Office Manager, Social Security Officer, and Regional/Sub/Divisional Office of ESIC to which the unit is attached regarding the change of the name of the factory/unit by also enclosing with the letter a copy of the deed/agreement etc. regarding such changes/transfer.
It is also submitted that a sub-code is issued based on the main factory/establishment, which is located somewhere in another region of ESIC. Therefore, in case only the Sales Office/Branch Office of a unit has been sold to another unit/owner, then in this situation, the facts appear to be different, and in my opinion, the appropriate Office of ESIC, as mentioned above, may be consulted and approached for necessary orders in the matter.