Some time ago I found this topic (or another one about Ramalingam), and I visit that website as well… Even though the question is “old” it may be said that such a transformation would imply mastery over all the bodies (and possibly the ability to travel on any plane).
This is a process of inner alchemy who lead to the Body of Light of Great Transference like in the Dzogchen, it is the true state of divinity ( all other are lower even the Rainbow Body is not as high as this one). The light body that remains is not a person or individual as we know it. It is a state of limitless God Light completely free from the previous humanity structures…
Regarding the practice this very similar to Dzogchen, Inner / outer Alchemy or Kundalini Siddha Yoga/Tummo.