If you are looking to downgrade your plan, here's how you can do it.
You will receive all your data when you upgrade again.
Downgrade your plan
Click your Profile in the upper-right corner.
Click Subscription next to Plan.
Select the plan to which you want to downgrade your plan.
Click Downgrade.
Once your downgrade is successful, you will receive a feedback form. Type your comments and click Confirm Downgrade.
Downgrade user add-ons
Click your Profile in the upper-right corner.
Click Subscription < Change.
Click Downgrade Add-Ons in the right corner.
You can choose the number of units and click Downgrade.
You can downgrade the number of units and click Downgrade. You can also resume the download and continue further purchase.