What is the difference between Dhamma Diksha and Dhamma Parivarta

I need your kind suggestion regarding different terms in our Buddhism. I wanted to know: - What is the difference between Dhamma Diksha and Dhamma Parivarta? - If a person from Hindu religion is getting Buddha Dhamma Diksha then will he be Buddhist on documentary basis? Or is Dhamma Diksha a kind of vidhi that the person needs to go through?