Each gym has an "Account Owner," the person who initiated the sign-up process with btwb. Only the gym's Account Owner will be able to change a gym subscription. If you aren't sure who the Account Owner is for your gym just visit the gym admin page to find out.
A gym's subscription can be changed at any time from the Admin Console. Go to the gym's menu in the top-right corner of the header of www.btwb.com and open up the Admin Console page.
Once you are in the admin console you will need to select the "Settings" tab on the left hand side of the screen, followed by the "subscription" tab. You can only cancel your subscription via the web.
The subscription page will allow you to view, edit, and cancel each of your subscriptions. Select the Members Pay subscription plan, This will end your subscription to btwb (and shift payment responsibility to your members.)