If you need to cancel or make a change to an Order Requisition, locate it on your Dashboard and open it to view the current status.
The status screen (above) includes available actions for the order requisition given its current status.
If your requisition is still in the approval process, it can also be found by clicking "View All" in the My Orders panel of your Dashboard.
In the image below, you can see that because the order requisition is in approval (and not yet being purchased), there is an option to delete the requisition, halting the approval process.
When you delete an order requisition, you will be given the option to keep the original cart so that you can adjust and resubmit.
Note - Punchout orders in approval can be deleted, but the cart remaining can only be edited in a few minor ways before the cart becomes no longer valid for the automated punchout process. If further edits are made, the order will need to be placed directly by the buyer.