Hello,

In this case the most efficient way to correct the mistake is this:

1. In module Sales Ledger >> Registers >> Receipts >> Create new Receipt;
2. In this Receipt, specify the Invoice No., which has been incorrectly connected to the prepayment (if the prepayment fully covered the invoice, you will have to type the Invoice No. manually, otherwise you can select it from Paste Special window).
Then, you need to specify the amount of the Prepayment, but with a negative sign;
3. In the same Receipt, on a second row specify the same customer and the same amount (only this time it should be positive). In the D flip you can specify the same number of prepayment that you incorrectly connected to invoice.

So, let's say you connected prepayment No. 001 of 100.00 GBP to an invoice No. 18001 and want to correct that. The Receipt should look like this:
Invoice No.    Prepayment No.        Amount
18001                                            -100.00
                    001                            100.00

Next thing you want to do is check the reports if everything looks okay. The following reports should be checked:
1. Sales Ledger >> Reports >> Sales Ledger - you can run it per customer and check if the Invoice became open again;
2. Sales Ledger >> Reports >> Periodic Customer Statement - check if the current customer balance is correct;
3. Nominal Ledger >> Reports >> Trial Balance - run for Debtors and Prepayments accounts - balances should match the data you see in Sales Ledger reports.

Let me know if you have some questions.

Kind Regards,
Pijus
HansaWorld Support