A wilted Plumeria may indicate underwatering or overwatering. If the soil is dry, water the plant thoroughly and let any excess water drain away. If the soil is waterlogged, allow it to dry slightly before watering again. Trim any wilted or damaged leaves to reduce stress on the plant. Place the plant in a shaded area for a few days to recover before gradually reintroducing it to direct sunlight. Monitor the plant closely and adjust watering and care as needed to revive the wilted Plumeria.