The recommended process is to clear the remittances and then reprocess as follows:
Unallocate the payments from the invoices.
Post a negative value Payment and allocate against the now unwanted one
Reprocess the remittance via the BACS process.
In some circumstances it is possible to move the payment type from cheque to bacs and for more information. To resolve this issue - our support team will need to investigate, run scripts or liaise with the hosting or development teams. Any Issues with contacting us, please see the following Get support in Access Financials.