Both Receipt and payment module have the feature.
the example will be base on the the payment module.
Common scenario where you would use the function is when you have to make a payment before the invoice is received.
, when there is a over-payment.
Step 1. Select the BP.
Step 2. Click the 'O' button on the left side of the detail section.
Step 3. in this section you will need to fill in the 'Document' and 'Reference'
For 'Document' field you can label it with something meaning full.
eg. Advance payment, Over-payment. Prepayment.
For 'Reference' field it is advise to use a unique name.
if there are multiple document where both 'Document' and 'Reference' are the same. they will be grouped together in the import screens.
to avoid this at least on of the fields should be different.
enter the value of the pre-payment document.
once the invoice is received you'll need to knock off the value.
you can click on 'Other Outstanding' to find the pre-payment document.
select the invoice you want to knock off. note you can import multiple invoices.
If you do not import the pre-payment document to knock off against another document , it will remain outstanding in the aging report.