I think that simply calling admissions staff would suffice, although it probably depends upon the university. I know that when both my brother and his wife applied to different schools in the same university, she heard back much earlier than he did. He simply called the law school and explained to them the situation, and his acceptance followed almost immediately. You certainly won't have marks placed against you for calling and having a matter-of-fact conversation. After all, the person on the other end of the line is human, and will most likely be sympathetic to your particular situation.