Passing RLMResults into a RLMArray for use in swapping objects. To avoid using sort index properties and rely on the array indices.

AppDelegate.m

#import "AppDelegate.h"
#import <Realm/Realm.h>

// Define your models
@interface Dog : RLMObject
@property NSString *name;
@property NSInteger age;
@end

@implementation Dog
// No need for implementation
@end

RLM_ARRAY_TYPE(Dog)

@interface Person : RLMObject
@property NSString      *name;
@property RLMArray<Dog> *dogs;
@end

@implementation Person
@end

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.window.rootViewController = [[UIViewController alloc] init];
    [self.window makeKeyAndVisible];

    [[NSFileManager defaultManager] removeItemAtPath:[RLMRealmConfiguration defaultConfiguration].path error:nil];
    
    NSArray *names = @[@"Rex", @"Jim", @"Max", @"Stella"];
    NSArray *ages = @[@9, @14, @4, @12];
    
    NSMutableArray *kennel = [[NSMutableArray alloc] init];
    
    for (int i = 0; i <= 3; i++) {
        // Create a standalone object
        Dog *mydog = [[Dog alloc] init];
        
        NSString *name = [names objectAtIndex:i];
        NSInteger age = [[ages objectAtIndex: i ] integerValue];
        // Set & read properties
        mydog.name = name;
        mydog.age = age;
        
        [kennel addObject:mydog];
        
    }
    
    NSLog(@"Current Kennel Description: %@", kennel);
    
    // Realms are used to group data together
    RLMRealm *realm = [RLMRealm defaultRealm]; // Create realm pointing to default file

    // Save your dogd and kennel
    [realm beginWriteTransaction];
    [realm addObjects:kennel];
    [realm commitWriteTransaction];
    
    // RLMResults are auto-updating container type, chages are reflected on disk in a transaction.
    RLMResults *results = [Dog allObjectsInRealm:realm];
    NSLog(@"Current Kennel Stored: %@", results);
    
    RLMArray * swappableArray = [[RLMArray alloc] initWithObjectClassName:[Dog className]];
    for (Dog *object in results) {
        // Create a standalone object
        Dog *dogStandAlone = [[Dog alloc] init];
        dogStandAlone.name = object.name;
        dogStandAlone.age = object.age;
        // Accessors cannot be mutated or stored.
        [swappableArray addObject:dogStandAlone];
    }
    
    NSLog(@"Swappable Kennel Description: %@", swappableArray);
    
    // Delete your initial objects
    [realm beginWriteTransaction];
    [realm deleteObjects:kennel];
    [realm commitWriteTransaction];
    
    // Swap stuff
    id tempObject = [swappableArray objectAtIndex:1];
    [swappableArray replaceObjectAtIndex:1 withObject:[swappableArray objectAtIndex:3]];
    [swappableArray replaceObjectAtIndex:3 withObject:tempObject];
    
    // Save your objects, they were copied over
    [realm beginWriteTransaction];
    [realm addObjects:swappableArray];
    [realm commitWriteTransaction];
    
    RLMResults *swappedResults = [Dog allObjectsInRealm:realm];
    NSLog(@"Kennel Swapped Description: %@", swappedResults);
    
    return YES;
}

@end