There are a few circumstances that can cause this error. Here are some additional troubleshooting steps:
1. Ensure that the change is associated with an "Open" Purchase Order. 2. If there are multiple changes sent for a single order, they will need to be accepted or rejected in the same order they are sent. 3. Ensure the order has not already been cancelled by the retailer.
If you are still unable to accept the Purchase Order Change, contact our Support team using the blue "chat" icon on the bottom-right corner of your Fulfillment account, or contact us at: 1-888-739-3232 option 1.