Voids an issued, sent, retrying, paid, or bad_debt invoice and sets its status to
cancelled. A draft or disputed invoice can not be voided; delete a draft instead.
The invoice must have no paid or processing payments, no in-flight payments, and no applied
patient credit; refund the payments in the Hint app first. Otherwise the request fails with
422 Invoice can not be cancelled.
Voiding means the service was delivered and the balance is forgiven, so quantities the
charges consumed (coverage allowance, prepaid package items, charge-item inventory) stay
consumed. To give them back, return the invoice to draft and delete the charge, or delete
the voided invoice.