This is what I understand - in the Hindu tradition (perhaps it's similar in Buddhist and Catholic traditions) you are supposed to enter a new life when you become a Sannyasi (monk). One of the initial rituals in many schools is to perform funeral rites for your former self. Through this process, you renounce your family, relations, and what you think of as your "identity". Then the guru gives a new name to the monk. Afterwards, monks are prohibited from talking about their purvashrama (previous life).