You may have entered a wrong supplier opening balance or entred a balance in error. Open the opening balance transaction to change or delete it.
If you have paid or allocated the opening balance, you must unallocate the payment first. You can then change it.
If it's already allocated, you can't edit the opening balance
For opening balance invoices, this means the customers paid the invoice.
For opening balances that are credit notes, you’ve allocated the credit note to an invoice or a refund.
Before you edit the opening balance, you need to unallocate it.

You're shown a message asking if you want to save the payment as a payment on account. Choose Yes. You can then re-allocate the payment to the amended opening balance later.
You can only create refunds for the exact amount of the credit note they are paying. You must delete the refund rather than unallocate it.
Once you've amended the opening balance, you can re-enter the refund if required.
