title: Updating Store with new rest url dynamically. Extjs4
body: <p>I have two tabs in my application. First show the search results in a grid and second tab has a grid (uses "Details store") which shows details. </p>
  
  <p>I am constructing rest url on click of search result. How do I dynamically update "details store" with new url to get new JSON records.</p>
  
  <p>One way is to use EXt.Ajax.request and get the results and use store load method. 
  Is there any more elegant way.</p>