Go to "Manage > Invoices". Set the proper filters (e.g. 'Paid payment status', for all programs in the LIVE program state')
Click 'Bulk Invoice Adjustment'. Choose the amount you want to add to these parents' invoices. Choose to notify Invoice owners by email (this option is selected by default). You have the option to add a message (e.g. "2nd Installment due Nov. 15th").
- No action will be taken on invoices in 'void' or 'refund' status.
- You can not use the Bulk Invoice Adjustment tool to reduce invoice amounts.