Yes.  You may cancel or downgrade at anytime.  If you have a premium Access Pass, and no longer wish to pay, you will be give a Free Lady Bug membership, so you can continue to read at least 1 new book per month.  If you are less than half way through your membership period, you may get a refund for the unused portion of your membership.  If you cancel your paid membership more than half way through the membership period, you will not receive a refund for that period, but all future payments will be cancelled.   Contact Support if you wish to cancel your membership.