Locked Event Handler or Event Handler Set
Processing
You can schedule these background jobs in SAP Event Management (SAP EM) to execute the following:
● Subsequent processing of event messages that arrive for an event handler at a time when SAP EM is locking it

For example, somebody saves a shipment that updates an event handler, while you are simultaneously trying to send an event message to SAP EM for this event handler. SAP EM does not process this event message as the data update from the shipment is locking the event handler. In order that SAP EM processes the event message for this event handler at a later time, you have scheduled the appropriate background job correspondingly.
● Assign an event handler once again to an event handler set that SAP EM is locking

For example, a colleague assigns an event handler to an event handler set. In doing this, the colleague locks this set. You simultaneously try to assign another event handler to this event handler set. To ensure that, in spite of the temporary lock, SAP EM assigns your event handler to the set, you have scheduled the appropriate background job.
On the SAP Easy Access screen for Event Management, choose Administration → Processing Control → Schedule Background Jobs for Event Management.