The Void Existing Invoice window appears.
Click OK..
Sage 50 automatically does the following:
Note: When you view
the voided invoice in the Sales/Invoicing window, you'll notice that it
has the same number as your original invoice but with a "V"
appended to it. Also, a large "Void" notice appears in red letters.
All totals and subtotals for the invoice appear as negative values:
If the original invoice covers an existing sales order,
negative values appear for the quantities
shipped.
If the original invoice did not originate with a sales order, negative
values appear for the quantities sold.