To change inventory back to "Fulfilled by Merchant":
Select the listings you want to include using the tick-boxes in the first column.
Using the drop-down menu, select "Change to Fulfilled by Merchant".
On the next page, review the listings you have selected. If they are not correct, click the "Go Back" button. If they are correct, click the "Convert" button.
Note: The system will reset the Quantity to 0 for each item.
It may take up to 15 minutes for your changes to propagate to all systems. Once complete, you will be able to view the listings on the All My Inventory view page, where they will be marked as "Merchant" under the "Fulfilled By" column.