If it is a "one-day checkout," the item is on Reserve. You canNOT renew the Reserve items you have checked out. You need to bring it back to the library and return it at the Circulation Desk on the 2nd floor. You will need to wait for a day to have another chance to check it out for one day again.
If it is a 2-hour reserve item, you will need to wait for 30 minutes after it has been checked in before you have another chance to check it out for 2 hours again.