put
https://rls.congacloud.com/api/billing/v1/line-items/custom-plans
This API enables you to update existing custom billing plans and their associated plan line items based on their IDs. You can update one or more line items in bulk.
This is especially useful for teams who need to adjust payment schedules, installment details, or other plan parameters after initial creation.
You cannot edit the custom plan if the proposal is accepted, the agreement is activated, or any order line item is activated.