The Volume is changed at equilibrium

A bigger volume means that more space is created for the participating particles in the equilibrium.
The principle is that such a change must be opposed by the equilibrium, and that is possible by creating more particles.
You can change here the equilibrium in different ways:
  1. directly in the case of gases, for example by pulling out the piston giving the cylinder more volume.
  2. indirectly by diluting in the case of liquids.
In both cases the effect is the same.

example: I2(g) + H2(g) 2HI(g) (at elevated temp)
In this example volume change has no influence, because at both sides of the arrows the number of particles is the same. Dislocation is useless.