Then put restrictions on it - pass a law that allows you to convert commercial to residential during X number of years and for that converted commercial to have

Then put restrictions on it - pass a law that allows you to convert commercial to residential during X number of years and for that converted commercial to have slightly laxer requirements than standard residential housing. Don't allow new residential construction to skirt the regulations and put a time limit on the law to keep property developers from simply building commercial with the off-chance of being able to convert it to residential if the market for commercial real estate doesn't rebound.