When the new SILO ILL system was released the Allow Renewals checkbox defaulted to unchecked. In most cases, because we were all new to this, the Lender did not check the box and the transaction was filled without allowing renewals. Now many of those early transactions have reached the end of the loan period and the status is changed to OVERDUE. Because these transactions were not flagged to ALLOW RENEWALS the borrower does not have the option to request a renewal through the system.
In order for the request-for-renewal button to show up on a transaction, the lender must check the Allow Renewals the box when responding to the transaction request as WILL SUPPLY.

Around May 20th, SILO changed the default setting of the Allow Renewals check box to be checked, allowing renewals on all transactions by default.
But on the those early transactions, which are now in the OVERDUE state, the lending library currently is unable to edit the overdue transaction to Allow Renewals or change the due date. (This feature is coming! Editing the due date is a feature improvement on the new SILO ILL system update list and will be implemented later.)
With a transaction in the OVERDUE state, and without the ask-for-renwal button appearing, the borrowing library must call or e-mail the lending library and ask for a renewal. If the lender agrees, settle on a new due date and monitor this transaction outside the new SILO ILL system. The transaction will remain in OVERDUE status, which both the borrowing library and the lending library will see in their queues, but both libraries should leave the transaction out there in OVERDUE status until the borrowing library is ready to return the item and can mark the transaction RETURNED.
This is a temporary situation and should not continue to happen because SILO changed the default setting of the Allow Renewals check box to be checked.