This transaction set enables a sender to cancel or delete a previously transmitted X12 transaction set. Typically, a trading partner who initiated an original transaction (such as a purchase order or invoice) sends the 998 to the receiving party to formally retract or void that submission. The core structure consists of the ST (Transaction Set Header) segment that identifies the 998 itself, the ZD (Transaction Set Deletion) segment that specifies which original transaction is being cancelled along with the reason for cancellation, and the SE (Transaction Set Trailer) that marks the end of the message. This straightforward three-segment structure allows for efficient communication of transaction withdrawals without requiring extensive supporting documentation.

For example, ABC Manufacturing might send a 998 Set Cancellation to XYZ Logistics after discovering that a purchase order (850) submitted the previous day contained incorrect line-item quantities. ABC’s trading partner system generates the 998 with the ZD segment referencing the original 850’s transaction set identifier and noting “Incorrect quantity” as the cancellation reason. XYZ Logistics receives this 998, matches it to the original order using the transaction identifiers in the ZD segment, and removes the cancelled purchase order from their system rather than proceeding with fulfillment. This direct cancellation mechanism prevents duplicate shipments and associated reconciliation issues.