I am not sure if you are referring to claiming Earned Income
Credit in prior years with a new SSN by amending the older returns, but that is
no longer allowed.
The Path Act of
2015 prevents retroactive claims of the EITC by amending a return or filing an
original return for any earlier year in which the individual or anyone listed
on the return did not have a SSN valid for employment.
Please see this
IRS article on the impact of the Path Act on EITC.
