On the base of debts that are in the result of contract or torts of new contracts could be formed whom they are named accessory contracts .Some of them discharge to debts such as guarantee ,assignment of debt contracts and Novation .And some of them are merely guarantee for obtaining of the main debt e.g. Pledge and Personal Surety(Kefalat). After formation of these contracts, it could be occur changes in the original debt or on the origin of that e.g. resection or termination. So the main discussion is the effect of changes on these contracts which in this paper we are concerning about the present theories and we state that the acceptable view by Parliament is the changes of the main debt on the contrast of Guarantees' contracts do not have any effect on the accessory contracts that discharge the debt.