Yes but it's a giant pain in the butt and not worth doing. Better to set up a cash account, and keep your margin account. Transfer your shares to the cash account (using the same brokerage, obviously) and then you can transfer them back to the margin account if you need them there for some reason. Like, for instance, CTIX gets above 3 so it's marginable and you want to borrow money to buy more CTIX on margin