You can take the money out of your account assuming you are not on full margin. The call is protected by the stock for upside issues of the stock rising.
However, one you take out the premium, you no longer are protected against downside risk. For example, say you sold an out of the money call for 2 points of premium, and then you took out $ 190, ie $ 10 for cost of transaction.
Stock then falls 2 points, you are now negative $ 200 in your account.