Core data:- How to update values in the array (Transformable)

I work on app that use Core data to save data in local device. In Core data i have save data in array using Transformable format but, i don't know how to update particular values in the array. My code for update Array is here

 NSManagedObjectContext *context = [self managedObjectContext];
   NSManagedObject *user = [NSEntityDescription    insertNewObjectForEntityForName:@"Type" inManagedObjectContext:context];
 NSError *error = nil;
 //Set up to get the thing you want to update
 NSFetchRequest * request = [[NSFetchRequest alloc] init];
   NSEntityDescription *entity = [NSEntityDescription entityForName:@"Type"inManagedObjectContext:context];
 [request setEntity:entity];
 NSPredicate *predicate = [NSPredicate predicateWithFormat:@"businessTypes == %@", @"Others"];
 [request setPredicate:predicate];

   AppDelegate *app = (AppDelegate*)[[UIApplication sharedApplication]delegate];
  NSArray *results = [self.managedObjectContext executeFetchRequest:request error:&error];

if (results == nil) {
    // This implies an error has occurred.
    NSLog(@"Error from Core Data: %@", error);
} else {
    if (results.count == 0) {
        // No objects saved, create a new one...
    } else {
        // At least one object saved.  There should be only one
        // so use the first...
        user = [results lastObject];
        [user setValue:@"Management" forKey:@"businessTypes"];
    }
}

if (![self.managedObjectContext save:&error]) {
   //Handle any error with the saving of the context
}
else{
  [app saveContext];
   NSLog(@"update value successfully");
}

and below is my save array in core data:

{
    businessTypes =         (
        "Social Bussiness",
        Marketing,
        Transports,
        Others
    );
},

so i want to update "Others" to "Management" in the array.

When i run this code i have no error but i don't update particular value at index array. thanks to help me.