subscription_expansion_conflict
The upgrade needs commercial/source reconciliation, another purchase holds ownership, or the request key names a different target. Staff subscription-terms, commercial-status and subscription-override writes also return this when an unfinished purchase reserves the commercial source; neither the account change nor its audit write commits. Cancel an undispatched quote or finish/reconcile a dispatched purchase before changing that source. No capacity or charge is created by quoting.
Problem shape
Every non-2xx response is an RFC 9457 application/problem+json body. The type URI below is stable and machine-matchable, so branch on the final path segment (the code) and treat the status as redundant confirmation. See the error-handling guide.
{
"type": "https://docs.vocapable.com/errors/subscription_expansion_conflict",
"title": "…",
"status": 409,
"detail": "…",
"instance": "/v1/…"
}