Hi Anu,
I haven't seen any program or standard way to re-process any particular event unless it's a LOCKED event.
In your case, your options are limited
1) Create a custom program to read back and re-post the event which you want to re-process.
2) If you have EM webui, manually post this event again.
In both the options, you are creating one more event ( one more entry in /SAPTRX/EVM_HDR and related tables ) but not exactly re-processing the old event. Also, unless you take care of your EE_RESET condition, it keeps resetting your Expected Event.
Let me know if you need additional inputs here.
Thanks,
Vishnu