To downgrade your Iconfinder Pro membership, please follow these steps.
Log into Iconfinder and go to Your account page.
Click the Change Plan button from the right side of the page in order to change your subscription plan.
Choose which Pro Subscription you want to continue with. On the right side of the screen, you will see the details of the new subscription plan and the prices. When you finish selecting the new subscription plan, click on the "Downgrade now" button to finish the process.
If you have multiple users on your Pro subscription, you have to delete these users from your plan before you can downgrade.