Namaskarams,
Janavasam is entirely different from Pattana Pravesam. Janavasam is a step before your marriage. It is now symbolically performed in our marriage functions. But Patta na Pravesam is for Sanyasins, Yogis. After their gurukulavasam/education entirely in a separate place, in olden days, it used to be guru asramam, the to be sanyasis and yogis when return to their area it is called pattana pravesam. Janavasam is for gruhasthals and pattana pravesam is for yogis and sanyasis. That is the difference.
