This article outlines how to void outbound shipping labels and inbound return labels for UPS.
Outbound Shipping Labels
UPS labels that will not be used should be voided within 90 days of creating the shipment.
Within the first 90 days, you can void a UPS package label from your ShipHero Order Details page. Once 90 days have elapsed, you will need to contact your local UPS customer service office for assistance voiding a UPS label.
Inbound Return Labels
UPS return labels that will not be used should be voided within 24 hours of processing the shipment.
Within the first 24 hours, you can void a UPS return package label from your ShipHero Returns page. Once 24 hours have elapsed, you will need to contact your local UPS customer service office for assistance voiding a UPS return label.