When scrolling down the Edit Tab menu, It is very easy to accidentally click on Void Invoice instead of Memorise Invoice. Then you have this voided invoice which is not what you want at all. So, you either need to be able to DELETE a voided invoice, or to EDIT it, or, a new feature, called UN-VOID, or at least an UNDO LAST ACTION button. The best idea would probably be that you could DELETE it.
A VOID is only complete when you save an invoice (or other transaction type), therefore to undo a VOID you simply cancel the transaction (noting the transaction number so you can find it again in a search) and the VOID will not save. This is essentially an UNDO LAST ACTION function.
VOIDED transactions are able to be deleted under the EDIT menu, and therefore already exists.
Finally, to re-create invoices (or other transaction types) which were deleted, go to Reports > Accountant > Audit trail (the user will require the correct permissions) and filter by the applicable dates / transaction type etc... All of the transaction details will be visible (show additional columns where necessary) to be able to recreate the transaction.