This article describes how you can disable the auto renewal for a subscription.
An active subscription.
Navigate to Subscriptions under your customer.
Click on the subscription for which you want to disable the auto renewal. In this example we are going to disable the auto renewal for the “Exchange Online (plan1)” subscription, click on the subscription.
Click on Edit.
On the information window about when you want to apply the changes, choose Now and click Continue.
Uncheck the “Renews On” checkbox.
click Save changes.
Agree the Terms & Conditions by checking the checkbox and click I Agree.
Now the auto renewal is disabled.