Retrieve and set Lookup value from related entity using XrmSvcToolkit in CRM 2013

function GetDetails()
{
    var EntityName, EntityId, LookupFieldObject;
    //LookupFieldObject = Xrm.Page.data.entity.attributes.get('new_studentid');
    LookupFieldObject = Xrm.Page.data.entity.attributes.get('cms_batch');
    // If lookup field has value then the code will only run
    if (LookupFieldObject.getValue() != null)
    {
        //Fetch and place Entity Id (GUID) and Name (String) form lookup field into local variables
        EntityId = LookupFieldObject.getValue()[0].id;
        //EntityName = LookupFieldObject.getValue()[0].entityType;   
            var obj = RecRetrieve(EntityId, "cms_batch");
        // In retrieved XML document check if it has accountnumber attribute
   //below is code to retrieve and set lookup        
         if (obj.cms_MeritCriteria.Id != null )
        {
              var lookupData = new Array();
            //Create an Object add to the array.           
           var lookupItem= new Object();               
           lookupItem.id = obj.cms_MeritCriteria.Id;
            lookupItem.typename = 'cms_meritcriteria';
           lookupItem.name = obj.cms_MeritCriteria.Name;
           lookupData[0] = lookupItem;          
            // Set the value of the lookup field to the value of the array.
            Xrm.Page.getAttribute("cms_meritcriteria").setValue(lookupData);   
            Xrm.Page.getAttribute("cms_meritcriteria").setSubmitMode("always");           
        }
        else
        {
              Xrm.Page.data.entity.attributes.get('cms_meritcriteria').setValue(null);
        }
      
         
    }
}

function RecRetrieve(_id, _entityname)
 {

 var _result;
    XrmSvcToolkit.retrieve({
        entityName: _entityname,//"Contact",
        id: _id,//, 1FED44D1-AE68-4A41-BD2B-F13ACAC4ACFA//
        async: false,
        successCallback: function (result)
        {
            _result = result;
        },
        errorCallback: function (error)
        {
           alert("Error");

        }
    });

    return _result;
}