The "Issue Refund" function on a project's credits and retainers page allows you to reconcile your books within Ivy by zeroing out unused credits and retainers in a project. You can utilize this function if there are leftover credits and retainers that have not been applied as payments over the course of the project. Please note that the actual refunded payment to your client will have to be done outside of Ivy because the issue refund function will not send any funds to your client - it is simply for reconciliation purposes.