This video explains how to perform an incremental SharePoint migration using OnDemand. It explains that there is no specific incremental button or option, but the migration tool understands if the content already exists on the target and will only update the target with new or modified content from the source. The video also covers the steps to perform the migration using the migration wizard.
For further details please check out our product page.
https://www.quest.com/products/on-demand-migration/