In Pandle, if you assign a payment to a customer or supplier invoice you will be unable to edit the original invoice until the payment is removed. This is to protect the integrity of transaction and avoid penitential errors being caused.
Finding and deleting the payment
An easy way to find the assigned payments to an invoice is to go to Enter Transactions > Customer/Supplier tab > View > Invoices
Clicking the blue hyperlink on the invoice will allow you to view the invoice and all allocated payments
You can then delete this payment, amend the invoice and re-add the payment.
Re-adding the payment
If the payment was processed through a bank account that used file imports or automatic bank feeds then you will find it under the 'Ignored' tab when entering your bank transactions ready to be processed again. If it was manual entry then you will need to re-enter the payment manually. It is a good idea to make a note of the payment details before you delete it.