http://www.sims2wiki.info/wiki.php?title=Game_Help:Cheats#Build_CheatschangeLotZoning [residential/community/greek/dorm/secretsociety]
Changes the zoning type of the lot. Before rezoning a lot using this cheat, make sure there are no Sims currently living in the lot. To use this cheat, enter the lot that you would like to rezone, and then enter the cheat, choosing one of these zoning options. Save and exit to neighborhood and re-enter the lot.