It doesn't. B is guaranteed to be !A and A is guaranteed to be !B. Changing either breaks the entaglement.
Also because in order to see what state is particle we need to interact with it, measuring its quantum state also breaks the entaglement.
Also because in order to see what state is particle we need to interact with it, measuring its quantum state also breaks the entaglement.
The action that breaks the entanglement is the update of A before reading B and not the reading of A or B.