Hi Anu,
Right now, we have only option to reprocess through SAPTRX/EH_LIST -> Header-> Reprocess Event Messages to reprocess same event message. The reason being, we should not manipulate reported event and post it as some company uses for audit purposes.
The ideal option would be post a new event instead of updating existing event as this will also enable to you track down how many events are not posted due to errors.
Regards
GGOPII