grandfather
ˈɡran(d)fɑːðə/
verbNorth Americaninformal
past tense: grandfathered; past participle: grandfathered

    exempt (someone or something) from a new law or regulation.
    "smokers who worked here before the ban have been grandfathered"
    synonyms:	exempt, excuse, make an exception of/for, give/grant immunity to, let off, release, exclude, exonerate; informallet off the hook
    "smokers who worked here before the ban have been grandfathered"

Translate grandfathered to
Use over time for: grandfathered