Property distribution

Property has co-ownership of me and my uncle. Property has ground floor and first floor. As per mutual understanding between us,Me and my family stay on the first floor and my uncle and her family stay at ground floor.but, on paper and in the eyes of law, there is no such mention that ground floor belongs to my uncle and first floor to me. Note that first floor is newly constructed legally and we just shifted there few months ago. My uncle says they want to make ground floor on his name and first floor on my name . I do not agree and want to keep whole property as co-owner as it is now. My doubts are, After changing it, uncle may not allow us to park vehicle on ground floor He may deny access to water tank build at ground floor common to both He claim that whole land belongs to him as they stay at ground floor. Note, his intention is to snatch property completely on his name Suggest ways Should I keep it as it is means co-owner means can I deny changing name If I can not deny, what should I do to ensure that land belongs to both of us even after change of name as first floor on my name and ground floor on their name I want to ensure access of vehicle parking equally to ground floor and access to common water tank on ground floor