Avikara means without change. It is confirmed in Bhagavad-gita that each and every living entity is part and parcel of the Supreme Lord, and thus his eternal position is to cooperate or to dovetail his energy with the Supreme Lord. That is his unchanging position. As soon as he employs his energy and activities for sense gratification, this change of position is called vikara. Similarly, even in this material body, when he practices devotional service under the direction of the spiritual master, he comes to the position which is without change because that is his natural duty. As stated in the Srimad-Bhagavatam, liberation means reinstatement in ones original position. The original position is one of rendering service to the Lord (bhakti-yogena, bhaktya). When one becomes detached from material attraction and engages fully in devotional service, that is changlessness. Akartrtvat means not doing anything for sense gratification. When one does something at his own risk, there is a sense of proprietorship and therefore a reaction, but when one does everything for Krsna, there is no proprietorship over the activities. By changlessness and by not claiming the proprietorship of activities, one can immediately situate himself in the transcendental position in which one is not touched by the modes of material nature, just as the reflection of the sun is unaffected by the water.