Q: Cant figure out how to unpreorder an album

A few months ago i accedentaly pre-ordered the "One Direction Midnight Memories" album when I wanted the delux album of it. So then i preordered that, but i cant figure out how to unpre-order the regularr album. And on top of that, they keep releasing new singles which makes me pay for them on both albums and its frustrating me. Could you tell me how i can unpreorder an album???