popping and pushing view controllers in same action

 MapsViewController *aViewController = [[MapsViewController alloc]
                                        initWithNibName:@"MapsViewController" bundle:nil];
     // locally store the navigation controller since
     // self.navigationController will be nil once we are popped
 UINavigationController *navController = self.navigationController;

     // retain ourselves so that the controller will still exist once it's popped off
 [[self retain] autorelease];

     // Pop this controller and replace with another
 [navController popViewControllerAnimated:NO];//not to see pop

 [navController pushViewController:aViewController animated:YES];//to see push or u can change it to not to see.

Or

 MapsViewController *aViewController = [[MapsViewController alloc]
                                        initWithNibName:@"MapsViewController" bundle:nil];


UINavigationController *navController = self.navigationController;

//Get all view controllers in navigation controller currently
NSMutableArray *controllers=[[NSMutableArray alloc] initWithArray:navController.viewControllers] ;

//Remove the last view controller
[controllers removeLastObject];

//set the new set of view controllers
[navController setViewControllers:controllers];

//Push a new view controller
[navController pushViewController:aViewController animated:YES];

In Swift:

let newVc = UIViewController()
var vcArray = self.navigationController?.viewControllers
vcArray!.removeLast()
vcArray!.append(newVc)
self.navigationController?.setViewControllers(vcArray!, animated: false)

In case newVc exists in a Storyboard:

let storyboard = UIStoryboard(name: "Main", bundle: nil)
let newVc = storyboard.instantiateViewControllerWithIdentifier("YourViewControllerIdentifier") as! UIViewController
var vcArray = self.navigationController?.viewControllers
vcArray!.removeLast()
vcArray!.append(newVc)
self.navigationController?.setViewControllers(vcArray!, animated: false)

Taken from https://stackoverflow.com/users/1619554/tomer-peled 's solution, so others can find it more easily.

This appears to be the best way to do it for iOS8:

UIViewController *newVC = [[UIViewController alloc] init]; // Replace the current view controller 
NSMutableArray *viewControllers = [NSMutableArray arrayWithArray:[[self navigationController] viewControllers]];
[viewControllers removeLastObject]; 
[viewControllers addObject:newVC]; 
[[self navigationController] setViewControllers:viewControllers animated:YES];

Swift 4 :

self.navigationController.setViewControllers[].. doesn't worked out for me. But I am able to solve the issue by holding a navigation controller in an instance variable and do push/pop operation. Thus, silently able to change controller without glitch.

  guard let navigationVC = self.navigationController else { return }  
    navigationVC.popViewController(animated: false)
    navigationVC.pushViewController(myNewVC, animated: false)

You can use this code to pop or push your controller.

For objective c

bool alreadyPushed = false;    
//Check if the view was already pushed
NSMutableArray *viewControllers;
if ( (viewControllers = [NSMutableArray arrayWithArray:self.navigationController.viewControllers])) {

    for (UIViewController *aViewController in viewControllers) {

        if ([aViewController isKindOfClass:[YourControllerName class]]) {
            NSLog(@"pop your view controller");
            [self.navigationController popToViewController:aViewController animated:YES];
            alreadyPushed = true;
            break;
        }
    }
}

//Push Fresh View
if( alreadyPushed == false) {

    NSLog(@"push your view controller");
    YourControllerName *YourControllerObject = [[YourControllerName alloc]initWithNibName:@"YourNibName" bundle:nil];        
    [self.navigationController pushViewController:YourControllerObject animated:YES];

}

For Swift

  var alreadyPushed = false            
        //Check if the view was already pushed
        if let viewControllers = self.navigationController?.viewControllers {
            for viewController in viewControllers {                    
                if let viewController = viewController as? YourControllerName {                                               
                    self.navigationController?.popToViewController(viewController, animated: true);                        
                    print(" Push Your Controller")
                    alreadyPushed = true
                    break                        
                }
            }
        }                        
        if alreadyPushed == false {                
            let YourControllerObject = self.storyboard?.instantiateViewControllerWithIdentifier("YourControllerIdentifire") as! YourControllerName             
            self.navigationController?.pushViewController(YourControllerObject, animated: true)

        }