They will eventually just end up giving half the delegates to Hillary and Half to Osama-Obama. That way the delegates will be seated but you can bet that Hillary will fight it like a junkyard dog.
Or, they could seat the delegations but bar them from voting for the first two rounds. After the second round, most delegates are released from their pledges and can vote their conscience. If it doesn’t go for three rounds, then, well, it’s not the DNC’s fault is it?