The Duplicate Shipment button lets you quickly create a new label based on a previous shipment's data.
From the Ship page, click on the shipment you want to duplicate. You'll find the Duplicate Shipment button at the bottom of the page, next to the the Refund Label and Export Tracking Data buttons:
Clicking this button will bring you to the Create a Single Label page, with the same address and shipment details pre-filled. You can review and edit all of the information before buying the label, making this a quick way to save time when creating Return Labels, multi-package shipments, or for sending out a replacement!