HTML
<select class="form-control" id="selectrequest" ng-model="selected request" ng-change="vm.selected_requested()">
<option value="pending" > Pending </option>
<option value="approved"> Approved </option>
<option value="rejected"> Rejected </option>
</select>
JS
vm.model=[{
name:'abc',
lastname:'xyz',
status:pending
}]
//デフォルトで保留中のアイテムを選択する必要がある vm.selected_requested = function (){
}