Parameter Date type not refreshing

Hi All

i have created 2 parameters of date type called startdate and enddate  in query editor and eneter values and used these values in the measures . I have added these parameters as Slicer in the report and i want to use as date input parameters , but the issue is the value is not updating it is always having same value what we given in query editor , how to make this parameter to accept new values and it should be used in the measurements