*** You cannot modify an invoice once the End of day is done (also meaning when an invoice is in the Archives). ***
 
 
Here are two recommended options:
 

Option A (Most popular)

- Manually write a note with a pen on the End of day report for your accountant... He will make the adjustments manually in the GL accounts.

Option B ( If the month is not closed )

 
Example
Invoice 7894 (450.00$) was paid by VISA on the 18/12/2015
 
- Reverse the invoice with the same payment method and the same date.
Results: Invoice 8440 (-450.00$) paid by VISA on the 18/12/2015
 
- Reverse the reversed invoice with same method of payment and the same date. 
Results: Invoice 8441 (450.00$) paid by VISA on the 18/12/2015