Classical yoga under Patanjali has 8 different "limbs" of yoga. The first "limb" is the Yamas or social contracts. The second "limb" are the Niyamas or contracts with oneself. The third "limb" is Asana or yoga poses, there are hundreds! The fourth "limb" is Pranayama or breath! The fifth limb is Pratyahara or turning inward!
In my opinion:
Pratyahara, is sense withdrawal, is changing your reality! As a human being our central computer (brain) receives its data through five channels (senses) which are sight, smell, taste, touch and hearing.
The data we receive through our senses is assimilated and stored in our brains. The purpose of pratyahara is to manage this input of data for a new experience. However, if we withdraw our senses do we shut down reality?
Well, yes and maybe no!
Like our sight which only sees a small percentage of the below spectrum of energy, our senses also perhaps only see a small amount of another spectrum!
And it is from this withdrawal of the senses that brings us to a heightened state of awareness!
Withdrawal of the senses allows us to turn inside.