title: How to remove/clear scope variable on ng-change
body: <p>I have a dropdown with a ng-change event handler:</p>
  
  <pre><code>            &lt;label&gt;Person:&lt;/label&gt;
              &lt;select class="form-control" ng-model="select" ng-change="change()"&gt;
                &lt;option value="0"&gt;a &lt;/option&gt;
                &lt;option value="1"&gt;b &lt;/option&gt;
                &lt;option value="2"&gt;c &lt;/option&gt;
              &lt;/select&gt;
  </code></pre>
  
  <p>On change i assign data from an array to $scope.person:</p>
  
  <pre><code>  $scope.change = function(){
          $scope.person = $scope.persons[$scope.select]; 
   };
  </code></pre>
  
  <p>The array:</p>
  
  <pre><code>  $scope.persons = [
         {'name': 'Peter'},
         {'name': 'John'},
         {'name': 'Mark'}
  ];
  </code></pre>
  
  <p>When a person is selected (for example $scope.select == 0/Peter) there is a possibility to add a value to that person ($scope.person.value) via radio buttons: </p>
  
  <pre><code>&lt;label&gt;&lt;input type="radio" ng-model="person.value"  value="1"&gt; Value 1 &lt;/label&gt;&lt;br/&gt;
  &lt;label&gt;&lt;input type="radio" ng-model="person.value"  value="2"&gt; Value 2&lt;/label&gt;&lt;br/&gt;
  &lt;label&gt;&lt;input type="radio" ng-model="person.value"  value="3"&gt; Value 3&lt;/label&gt;&lt;br/&gt;
  </code></pre>
  
  <p>When a value ($scope.person.value) is added to a person, and i change the dropdown I want to remove/clear that value. So that when you reselect that person in the dropdown $scope.person.value is undefined.   </p>
  
  <pre><code>  $scope.change = function(){
      //This is not working
     delete $scope.person;
     // This is not working either
      $scope.person.value = '';
  
      $scope.person = $scope.persons[$scope.select]; 
  
   };
  </code></pre>
  
  <p>I want to know how to clear the value stored in $scope.person.value on change of the dropdown. Now the variable is still defined when I reselect the person. <a href="http://jsfiddle.net/martijnbar/t1n8p6qc/5/" rel="nofollow">Here is a working example.</a>   </p>