The bill doesn't need to be reversed it can just be reprinted through Advanced Report Execution, make sure you have the name of the template needed:
From the Main Menu select Advanced Report Execution.
Put in the Search at the top of the screen the name of the bill template.
Double click on the correct one.
Put in the TX number for the bill you wish to reprint (this can be found in the drill down on the posting0
Select RUN.
This will produce the bill you require.