Susan:
Reversing a cheque will make the invoice outstanding again.

Think of it this way: If you invoice me for $1,000, I'll send you a cheque. But if you don't receive it, then I'll Reverse it. I still owe you the money. Therefore the invoice is still outstanding.

There are other circumstances when you also want to cancel the invoice (ie. the invoice was entered in error originally). But Adagio doesn't know your intentions concerning the invoice and will make it outstanding again.

Therefore, if you want to "cancel" the invoice, you must enter an Adjustment to adjust the invoice to $0.00.

The exception to this discussion is a "Cash Invoice" cheque. For those cheques, you do have an option in the AP Cheque Reconciliation to also "reverse" the invoice when the cheque is reversed.