This doesn't work because there is no moment at which the state is 'known' or 'detangled'. There is no way to tell, by observing one particle, when the other particle was observed. If there was you could send a signal with it, which would be no good.
Not in the way that you're imagining. Otherwise, you could easily communicate by repeatedly observing and then unobserving until finally you see the bit that you don't want to send, and then you let it be.
The universe is a strange place.