What modification is done on the Ti plasmid of Agrobacterium

What modification is done on the Ti plasmid of Agrobacterium tumifaciens to convert it into a cloning vector?

Tumour inducing (Ti) plasmid of Agrobacterium tumifaciens is modified into a cloning vector by removing/altering the gene responsible for its pathogenic property.
This is so, that it does not cause harm but can act as a delivery system for the genes of interest into a variety of plants.