You cannot cancel or delete either, but you can just stop using either one. Anything you already purchased with the newer one can only be updated or re-downloaded using that AppleID - purchases are tied to the AppleID logged in with at the time of purchasing.
You can log in and out of the store with any number of AppleIDs though. So just log out with the newer one and go back to logging in with and using the older one. Do not forget the password for the newer one though, as you will need that to update anything you've already purchased with it.
P.S. to log out, just open the store app, scroll to the bottom where the account shows, then log out, log in with the alternate AppleID and shop away.