Cloud Library e-books and e-audiobooks cannot be renewed. However, if there are no holds on the title, books may be checked out again and re-downloaded after your loan period expires. Otherwise, you will need to place a hold on the title.
OverDrive e-audiobooks and e-books:
Users can renew a borrowed title if there are no other holds on the title. Appearing next to the title in the Loans area of your library OverDrive account, the renew option becomes available three days before the title is set to expire. Customers may only renew a title one time. If there are existing holds on a title, the Renew button will not work and will look grayed-out. See the following link from OverDrive’s Help menu for step-by-step directions to renew titles.( http://help.overdrive.com/customer/portal/articles/1481523-how-to-renew-digital-titles )