By updating your BOMA monthly plan to an annual plan you will save 15%. To update your plan, navigate to Settings -> Billing, and click on the Update Plan button.
You'll be presented with a box that contains a small button that can be switched between 'Per Month' and 'Per Year'. Make sure you have selected Per Year and then click Continue.
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Next you'll be asked to enter your credit card details and then click Submit.
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Further Reading:
How to update your credit card
BOMA payment plan options - monthly vs annual plans
What happens if I cancel my subscription to CCH Business Fitness?