Why are you wanting to know this?
Just curious. I do not believe you can do that. There may be some type of changes that can be made like a white report type of thing which is used to change apartments to condos. I personally have never heard of condos changing to PUD's. What benefit are you looking for? I would really like to know!
I think the best place to start is your city planning dept.
Prudential CA Realty