Re-issue an online bill payment that was processed by mistake

1) Call your bank and place a stop payment on it.
 
Note: Bank may sometimes charge you for Stop Payment Request.
 
2) Void the bill payment in NetSuite. The Void button will appear in View mode if your accounting preference Void Transactions Using Reversing Journals is enabled. Otherwise, you can see the Void button in edit mode.
3) You will receive a notice Stating "Payment was already processed and completed, voiding the transaction only in NetSuite." Click OK
4) The bill will now change from Paid in Full to Open. You can now process another payment.
 
Note: Enhancement 194943 is filed to add this documentation in the Help Guide.