https://github.com/ingadhoc/account-payment/blob/c99319c94da5d38553ece58d37002c528fe2b27d/account_withholding/models/account_payment.py#L78 When try to action_draft Odoo raise "You cannot modify the taxes related to a posted journal item, you should reset the journal entry to draft to do so." We workaround this using _write and None for vals: def action_draft(self): ''' posted -> draft ''' withholdings = self.filtered(lambda x: x.tax_withholding_id) for withholding in withholdings: liquidity_lines, counterpart_lines, writeoff_lines = withholding._seek_for_lines() liquidity_lines._write({ 'tax_repartition_line_id': None, 'tax_line_id': None, }) return super().action_draft()