Write an open invoice off as bad debt, moving it to uncollectible. This is terminal: an uncollectible invoice cannot be paid, voided or credited afterwards.
Writing off clears the debt: in the same transaction each line item gets an opposite memo entry on the policy ledger, so the policyholder no longer owes the invoice. The line items are kept, so the response carries them and the charges can never be placed on another invoice.
A credit note can never be written off, 409: it is allocated to the invoice it credits on creation, so its status is fixed.
Invoicing is opt-in per organization: unless the invoicing feature flag is enabled for your organization this endpoint returns 403.
The invoice cannot move to uncollectible from its current status. Only an open invoice can be written off.
Invoicing is not enabled for the organization, or the caller is missing the invoices:mark_uncollectible permission.
No such invoice, or the caller's user group does not grant access to its policy.
The invoice's linked payment has already gone to the bank and can no longer be cancelled (reconcile the payment first), the invoice is a credit note, or the invoice was modified by a concurrent writer.