The best time to report an orchid is when new roots are just starting. They can grow freely into their new potting mix. However, where poor growth, in a potting medium that has broken down, repotting at the wrong time may be the best and only time to save the plant.
"The Time-Life Encyclopedia of Gardening: Orchids", Time-Life Books, Virginia, A.Skelsey.
"How To Grow Orchids", Sunset Books, Lane, California.
"Orchids, A Golden Nature Guide", Golden Press, New York.
"Simon & Schuster's Guide to Orchids", A Fireside Book.