You can easily cancel and reschedule an Ad Shop ad from your Orders > Ads page.

To cancel/reschedule an ad: Click on the three dots under the "Ad Ref ID" column, as shown in the image above. 

You can also download the IO by scrolling to the right and clicking on IO icon under the Order Ref ID column. That will prompt the platform to automatically download the IO. Take a look at the image below for reference: