Once the checkout period has expired, eBooks are automatically returned / checked in to the EBSCO collection for others to access.
IMPORTANT: If you want to return an eBook prior to its expiration date:
ATTENTION: DO NOT select "Remove from Library." This will remove the file from Adobe® Digital Editions, but the eBook will still show as checked out to you in your EBSCO Account. If you accidentally remove the file from Adobe® Digital Editions instead of returning the eBook, you will have to re-download the file, open it in Adobe® Digital Editions, then follow the steps above on how to return an EBSCO eBook.
If you are unable to remove the item from your Adobe Digital Editions interface after the due date has passed, you will need to look for answers in the Adobe Digital Editions Community forum at https://forums.adobe.com/community/adobe_digital_editions