-You have to go bankrupt in order to have the option to retry a level. Do this by getting a negative cash balance. First, go to the Upgrade screen and sell all bought upgrades. Sell all your movies, then go to the "Loan" screen. Raise your daily repay amount to a value greater than what you have. Click "Accept" and you should go bankrupt. You can now replay the level.
-To become bankrupt, first borrow $5,000 from the loan shark. Have no movie playing and start the day. Keep doing this. Eventually a message will appear, stating that the loan shark demands his loan back. If you have $5,000 or more, do not start the day. Instead, look for a movie that costs enough for you to drop below $5,000 and buy it. You can now start the day. At the end of the day, a message will appear, stating "We steal your credit". They should take $5,000 and you will then have negative money. Start the day to restart.
You can always borrow from the bank or the loan shark, or even both of them. Occasionally all it takes is a little extra money to make it. If you are in real trouble, sell back the upgrades that are not necessary for making it to the next round.