Hi ch496, 

Thanks for joining the thread. You can follow these steps to downgrade your subscription. 

1. Go to Gear icon and select Account and Settings. 
2. Select Billing and Subscription. 
3. Select Downgrade subscription.
4. Select the plan you would like to use and confirm. 

For more detailed information, you may check on this article: Upgrade or downgrade your QuickBooks Online subscription.

Let me know if you need any help with your subscription. Have a great day!