If your plant has a healthy environment, with large green leaves, were not hurt or suspended, cut flowers, old stem top, just above a "node" and just below the lowest bloom. The plant will often send a flourishing new branch there. If your plant has thin, wilted leaves, or if the plant is small, with leaves only 3 to 4 inches long, it is best to cut the flower stem all the way down, so the plant does not weaken in flowering new right to same. Water thoroughly and fertilize your plants to build it back into shape for a blossoming future in a brand new strain. This can take up to a year or more, as Phalaenopsis, like most orchids, a plant growing relatively slowly.