I prefer to transplant my azaleas in midwinter or early spring. I prefer this as many Satsuki's bloom in May or June and the hot weather at this time of year makes transplanting dangerous, in my view. Some bonsai books recommend that the roots be washed completely when transplanting, leaving no old soil on the plant. I have done this, with both successes and failures. I am convinced that soil must be removed up to the underside of the trunk, even if it takes a Dremel tool to cut away the old soil.
Packed soil has no aeration and can support no feeder roots or mycorrhiza.
Some azaleas will begin growth prior to flowering. If new shoots develop at the base of flower buds, they should be cut off. If new growth starts on non-bud bearing shoots they can be left or cut depending on the desired styling design. Shoots left on prior to flowering will take energy from flower development and can result in some smaller flowers or bud drop. After the flowers fade they should be cut off to the base of the flower stems.