Experiment to determine if two photons communicate by sending a message back in time

This is a pretty interesting experiment to even think up. John Cramer from Washington University is going to test if "spooky action at a distance" happens by communication that is sent to the past. Spooky action at a distance, is what einstein described as the communication that takes place between two entangled photons, where one photon reacts instanteniously to what happens to the other photon. This would require communication that travels at a speed faster than light. And einsteing said that nothing travels faster than light. Many current theories try to describe this phenomenon by eliminating communication. Cramer will be conducting test to prove communication, and then also testing for retrocausality, which he believes is subatomic particles being able to communicate backwards and forwards in time.

He will test this by shooting a ultraviolet laser into a special crystal which will release two low-energy entangled photons. Photon one will be sent through a slit screen which will detect it is either a wave or a particle, the second photon will be sent through 6.2 miles of fiberoptic cable, which will delay it's arrival at a movable detector by 50 microseconds. Moving the detector will determine whether the photon is detected as wave or particle. The experiment will test if the detecting the second photon as a wave or particle will change the way the first particle is detected. If it does, and since the second particle is detected 50 microseconds later, this should prove retrocausality.

I don't know if it will nescesserily prove that communication travels into the past, or maybe there is some other form of communication. Regardless, I'm not sure how this experiment will work. Once you detect the first particle, haven't you already determined what the second one will be. And if you can specify how the second photon is detected by moving the detector, then how do you redetect the first photon? I'm going to ask Reddit.