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];