You would. But with some airlines you can change to the freq flyer number of another ffp after getting a benefit. AA does not allow a change to the ffn after getting a status benefit. But not all airlines have the same policy. The physical card can get entry to some lounges, albeit at the risk the lounge attendant changes the ffn in the reservation. Is very inconsistent across OW airlines and not dependable.. Changing ffn has risks. Keep the physical boarding passes.