[TheMoon (OP)]

One cannot expect that a direct measurement of one particle in a coupled state would mean this would bring about any changes in the other particle.  But perhaps in some ways, those changes can be achieved.  Perhaps, in order that measurement of particle a have any effect on particle b, the measuring apparatus must mimick the photon.  The reason is, each particle a and b has potential.  Not all of these potentials will be realized however in a single time-frame.  The photon therefore, posessess the most potential.  It has to be ready to serve data about particle a behaviour to the observer.  So, rather than to begin with arbitrary measurement of particle, one begins with a series of arbitrary measurements of the photon.  After arbitrary measurements on the photon have been made, the result should be a series of potentialities, pertaining to the photon and therefore particle a and b.  Throughout this measurement process, information acquired about particle a, directly affects particle b.  It is unlikely one would gain a classical measurement, though at this stage not impossible.  The more arbitrary measurements are made on the photon, the closer one gets to a full description of both particles.  That is to say, an observer at particle a, making a measurement would have no effect at all on particle b, because of a resitriction in potentialities.

[PmbPhy]

One cannot expect that a direct measurement of one particle in a coupled state would mean this would bring about any changes in the other particle.

But you asked about affecting measurements made and not changes in the particle. Those are different concepts. If two electrons are in a spin triplet state then measurement of the spin of particle a will mean that when you measure the spin of particle b it will have the opposite spin.

Perhaps, in order that measurement of particle a have any effect on particle b, the measuring apparatus must mimick the photon.  The reason is, each particle a and b has potential.

Potential comes from being in the presence of a force. There is nothing that can exert a force on a photon and likewise there is no reason to assume that a photon can ever have a potential to it.

[TheMoon (OP)]

It was not word perfect and I am looking for fault with this.  I meant that any arbitrary measurement of a system is equal to having mimicked the photon and that that is how I perhaps should go about the measurement process, to determine whether the act of measuring particle a would have an effect on particle b.  I propose that it would, through a series of arbitrary measurement.  Assuming I know nothing about particle a or b; and so causal relations would only become significant as I learn more about a, through a series of arbitrary measurement.  Here, I hoped to find that the act of measurement on a would have an instantaneous effect on b.  That the effect would not occur if measurement was not arbitrary, since non-arbitrary measurement would only be correct within a certain average.