With the exception of edits made to the accounting code, edits made to a product, rate plan, product rate plan charge, or product feature does not affect existing subscriptions that contain these items. When a product's accounting code is edited, the changes are not reflected within the subscription. However, the updated accounting code are propagated to the invoices export file. This allows the invoices export file to properly map the invoice line items to the customer's accounting system.
Go to the product detail page at Products > Product Catalog in the left-hand navigation section. On the product detail page, click edit in the Product Information section.
Billing Timing cannot be changed if the rate plan is used by a subscription.