Sure! The influencer can cancel the request while the status is ''Ordered''.
If the client accepts the request, the influencer can not cancel the order anymore.
On the "Request" tab under "Others", you will be able to see all the cancelled requests (also including the automatically cancelled requests because of campaign out of stock).
If you want to see the split between these two categories of "Cancelled", you have to go on the "Reports" tab, click on the "Operational" section and you will see the split between "Cancelled" and "No stock".