Use a nil-targeted action to message a view controller higher up the responder chain without introducing coupling

gistfile1.m

// in some parent view controller's header file
- (IBAction)yourActionNameHere:(id)sender;

// implementation does whatever you want

// Now, from any call site, as long as you're on the main thread
// just post an action to nil and it will be sent to the first responder, 
// then all the way up the responder chain until it finds your view controller

[[UIApplication sharedApplication] sendAction:@selector(yourActionNameHere:)
                                           to:nil
                                         from:self
                                     forEvent:nil];