If preparing more than 2 hours ahead, assemble, cut, and then store the sandwiches in a single layer between sheets of waxed paper in an airtight container in the refrigerator. For food safety, keep the sandwiches chilled until serving and do not leave them at room temperature for more than 2 hours (or 1 hour if it’s especially warm).
Any leftovers that have sat out too long should be discarded, as the cream cheese filling is perishable. If you need to transport them to church or a picnic, pack the tray in a cooler with ice packs to keep everything at a safe temperature and just uncover the tray when you walk in—the ladies will take it from there.