Suppose you have the EPSG:3021 coordinate system definition, which in WKT presents the datum as:
DATUM["Rikets_koordinatsystem_1990"]
but, for better ESRI interoperability, the user prefers the name D_RT_1990
In C#
var dat = TGIS_Utils.CSDatumList.ByEPSG(6124);
TGIS_Utils.CSDatumList.Fix(6124, "D_RT_1990", dat.Ellipsoid.EPSG, dat.Transform.EPSG);
In Delphi
var
dat : TGIS_CSDatum ;
begin
dat := CSDatumList.ByEPSG(6124) ;
CSDatumList.Fix( 6124, 'D_RT_1990', dat.Ellipsoid.EPSG, dat.Transform.EPSG ) ;
end;