Kiran Madhu 26 November 2018
Sidharth Nair 28 November 2018
There is no such legal process because right of freedom to profess a religion is a fundamental right granted by the Constitution of India.
If you want to convert to Christianity, you need to get in touch with local parish or pastor of the church and after they are convinced, they may admit you in an informal way for instructions.
This process may take some time as per whims of the church. Once you are IN and church priest/pastor is convinced of your intention and growth, they will baptise you as per theirs schedule.