No. If the directory already has items assigned to a level, it can´t be disabled. You also can´t choose a Default Location if there are items from different locations for that level.  Also, you can´t enable a Location Level if there are child levels enabled and non assigned items to that level you are trying to enable. For example: if the directory is using country, state and city, and there are items registered, you can enable neighborhood, but you can´t enable region because in this case the system will not have regions and states assigned. So, is extremely important decide your locations options before inserting data in directory. 