Many organizations select cloud computing because of their unlimited storage, computation and high bandwidth. Service based Application is composed by number of possibly independent services available in a network which perform the desired functionalities of the architecture. Service-based applications need to dynamically recompose themselves to self-adapt to changing QoS requirements. QoS means performance of the network. Hence, if the application wishes to show a different stage of QoS, it can do so by altering its part of the web services.