If you have selected to unapply some or all of a payment you are simply removing the link between a payment and the invoice/order. This will not refund or cancel the payment, but leave it in an unapplied state which will allow you to do a refund or cancellation, but will also allow you to apply to other orders/invoices in the system.
Select the amount you want to unapply.
You can unapply payment from specific products so you can select only a few or all of the products from a specific invoice. You can also unapply from one invoice but not another if you choose.
Decide whether or not to cancel the invoice.
If some payments will remain applied and you will be adding payment later you may wish to keep this at No so that the invoice remains active. However, if you are uanpplying all payments and do not intend to reapply them to this invoice you can cancel the invoice here.
Check the products the amounts being unapplied from the invoice you selected in the (details) link.
If there is only one product on your invoice this is not necessary, but if there are multiple products you may wish to select some and not others.
Select the products to unapply payment from and update totals.
This link will show you which products the payment is being unapplied from. If there are multiple products listed you can select some and not others to adjust the amount that you are unapplying.