| eventIdentifier | BusinessEventIdentifier | Individual parties should only use a single event identifier to identify a retraction.
Platforms providing services on behalf of both parties in a transaction may provide
event identifiers for both parties; in this case it is up to the recipient (the trade
repository) to validate that the event IDs refer to the same event.
| Business event identifier. | | 0-∞,
ncf | This is not used in messages to the repository. |