There are many scenarios where reverting a cancelled order is necessary. One example I've ran into is that you receive a notification that the item has already shipped just after sending the cancellation request.
If you've already printed your cancel request to the factory, then this will walk you through the process of how to revert the cancellation.
With the order open, go to the Action menu and select the option for "Revert Cancellation"
Then select the lines that you want to un-cancel. (Tip: clicking the "All" button at the bottom will check all the line items)
Just like in the Cancellation Request you have to type in a reason for this change.
Select the Output to option that you want OASIS to print to. Then press print and send the information to your factory.
If this is for internal purposes only, you will still need to print the document, just choose the PDF file option.
Your order will now look like a regular transmitted order again. The only difference is in the top center you'll see a red bar noting that the order has had cancelled lines on it before.