Specify requirement for a REST server : I am writing the requirements of a REST web-sever that needs to be implemented. One of the non-functional requirements is that each function (component) of the system can be activated or deactivated independent ob the other ones. 

To make it more clear, the web server offer different services, the services provider should be able to deactivate one of the offered services at any time without affecting the other ones. 

Is there a word describing this specification that could be wrote in the requirements and make a developer understand the needs ?