The USPS Package Pickup Change Web Tools API allows developers to change certain data in the original package pickup schedule request. Changeable data includes the number and types of package services, the weight of the packages, and the location of the pickup. Developers will need to enter the address and confirmation number for the pickup. This information must be identical to that which was entered when the pickup was scheduled.
This API is part of the USPS Web Tools API library which provides access to USPS data free of charge.