public void partialTransferOfOwnership(Person seller, Person buyer, int shares) throws BadSellerException {
		// TODO Auto-generated method stub		
		CorpMember corpSeller = null, corpBuyer = null;
		for (CorpMember member: members)
		{
			if (member.person == seller) corpSeller = member;
			if (member.person == buyer) corpBuyer = member;
		}
		if (corpSeller == null || corpSeller.ownership < shares) 
			return;
		if (corpBuyer == null)
		{
			corpBuyer = new CorpMember(buyer, shares);
			members.add(corpBuyer);
			corpSeller.ownership -= shares;
		}
		else{
			corpBuyer.ownership += shares;
			corpSeller.ownership -= shares;
		}
		if(corpSeller.ownership <= 0) {
			members.remove(corpSeller);	//No remote drop. This way we avoid concurrency errors during death.
		}
		updateCheapest();
	}