[Gatsoft]

LB_NOMBRES.Caption:=SearchAndReplace(LB_NOMBRES.Caption,'É','E')

Código Delphi [-]
FUNCTION SearchAndReplace(sSrc, sLookFor, sReplaceWith : string) : string;
VAR
   nPos, nLenLookFor : integer;
BEGIN
   nPos := Pos(sLookFor, sSrc) ;
   nLenLookFor := Length(sLookFor) ;
   while (nPos > 0) do begin
     Delete(sSrc, nPos, nLenLookFor) ;
     Insert(sReplaceWith, sSrc, nPos) ;
     nPos := Pos(sLookFor, sSrc) ;
   end;
   Result := sSrc;
END;