The problem is modifying the spin of one entangle particle breaks the entanglement (decoheres the system).
The only thing you can do is observe the one, then observe the other. The collapse of the wave-function under observation preserves the anti-correlation of spins (in the usual example of an entangled pair) so the two observers read opposite spins (up-down or down-up), a prior agreement as to how to interpret them (1st observer takes up to be 1, down to be 0, while the 2nd takes down to be 1 and up to be 0) gives them a common bit. Doing this repeatedly gives them a common random bit string which can be used as a one-time binary pad. That’s all it seems you can do with this, whether it’s implemented by Planck-scale wormholes or by real physics not being “physically realistic” (a notion that means looking like classical physics in certain ways).
The two will dance randomly in sync across the space, but one can’t be tweaked to get something to happen to the other one. OK. Still a challenge to conventional ideas.
Even if they can dance, if they could somehow be made to dance in a non random way, then breaking the dance of one particle would be immediately visible on the other end.
It would offer a way to communicate quickly with deep space craft, if you had enough such pairs between earth and the craft. You would sacrifice a pair for each signal.
It seems to me that the very act of ‘entanglement’ vs ‘non-entanglement’ would create a communications window. Any time you can have two separate states of something, be it a particle or an iceberg, you have a mode of communication..............