Changes in Inventories is a line item on the Statement of Cash Flow that looks at the change in inventory from the previous reporting period to the current reporting period.

Changes in Inventory = Inventory for Current Reporting Period - Inventory from Previous Reporting Period

Let's say Company A had $1,000 in widgets at the end of last quarter and has $2,000 in widgets at the end of the current quarter. As a result, the changes in inventories for the current quarter are $1,000 (2,000 - 1,000) in widgets.