Prepaid subscription swap product

Topic summary

Main issue: How to swap products on a prepaid subscription’s FulfillmentOrder via API. Request for whether Shopify supports changing items on an existing FulfillmentOrder, or any workaround.

Key constraints and definitions:

  • FulfillmentOrder (FO): the fulfillment-specific record for an order; it is immutable. Any order edit creates new FO(s).
  • Prepaid subscriptions: customers prepay for multiple future deliveries. Shopify docs state billing cycles for prepaid subscriptions cannot be edited.

Proposed approaches and outcomes:

  • Billing Cycles were suggested but rejected because prepaid billing cycles aren’t editable and wouldn’t update existing FO(s).
  • Shopify guidance: edit the order (which will generate new FO(s)) and proceed with those.

Implementation roadblocks:

  • Request for concrete mutations to “adjust the order.” A provided documentation link returned 404.
  • Attempt to use orderEditBegin on a prepaid order with scheduled FO(s) returned: “The order cannot be edited.” (GraphQL error shown in code snippet).

Status and open questions:

  • No confirmed method via Subscriptions API for prepaid cases; order editing appears blocked for prepaid orders with scheduled FO(s).
  • Unclear if this is expected behavior or a bug. Pending: correct docs and explicit mutation/process guidance. Discussion remains open.
Summarized with AI on January 30. AI used: gpt-5.

@ShopifyDevSup , thx for the answer.
Do you have an answer to @keila2k question?