Need to delete a credit memo in Release status

Hi,

Credit button is  disabled in the projects invoice review from for the migrated invoices ( from Libra) . But User had credited the migrated invoice through the lines form.

Now the credit memo created is being rejected in Oracle receivables (Autoinvoice program giving error as the migrated invoices are not properly accounted ). 

Is it possible to delete a credit memo in Released status.

Thanks in advance