Partially Update Signing Request

Update signing request properties, a single recipient, OR a single field. Cannot update multiple entity types in one request. Cannot update after signing request has been sent, completed, or cancelled, except for a seal swap (see seal_participant). A seal_participant that names a seal answers 404 NOT_FOUND when the seal does not exist or belongs to another company, and 400 SEAL_UNAVAILABLE when the seal is revoked, deleted or not the current version of its lineage, and also when it is limited to a workspace other than the signing request's. These answers are for adding a seal participant and for changing its seal. A seal swap (swap_to_seal_id) answers differently for the new seal: 404 NOT_FOUND when it does not exist, belongs to another company or is limited to a workspace other than the signing request's; 409 SEAL_UNAVAILABLE when it is revoked, deleted or not the current version of its lineage; 400 SEAL_FIELD_REQUIRED when the seal participant has no stamp field on the signing request. Adding a seal participant or changing its seal answers 503 SEALS_DISABLED when organization seals are not enabled. Adding a seal participant requires order (see the order contract). A field that belongs to a seal participant accepts only position and page_number changes; every other key of field, recipient_id included, is ignored.