Any payments or partial payments that have been allocated to an invoice are displayed in the Totals section of the invoice.
To un-allocate a payment from an invoice follow these steps:
1. Open the relevant invoice and scroll to the bottom of the page.
2. Click the "X" icon next to the payment(s) that you want to un-allocate.
3. Confirm that you want to remove the payment allocation.
Unallocating a payment not delete it -- the payment or credit will still be available for allocation to other invoices. If you want to remove a payment entirely, follow the steps in this article: Deleting a Payment.
For unallocating credits follow these instructions: Unallocating a Credit Note.