I believe each particle is at two places at the same time, or, alternatively, has a double. Do something to its double kight years away and it will be immediately affected.
I think the only thing you can do is observe it.
How do we find those two specific particles out of an infinity of particles that exist ? Are they labeled ?
How do we know for sure that only two particles are 'linked' ? Maybe when we change the 'spin' of one particle (which can't be determined for sure but is an assumption because we don't know what it's spin 'was') it changes the spin of HALF the particles in the Universe.