How can I process multiple change orders on the same document concurrently?

There can be only one active change order on a purchasing document at any point in time. If you have a change to propose and there is an active change order on the same document, you will need to wait for that change order to get processed.

As the buyer on a purchasing document, the application let's you prioritize your changes by allowing canceling the current change order even if it's not initiated by you and creating a new change order for you to propose your changes.