Change button text from Xcode?

Yes. There is a method on UIButton -setTitle:forState: use that.

UIButton *myButton;

[myButton setTitle:@"My Title" forState:UIControlStateNormal];
[myButton setTitle:@"My Selected Title" forState:UIControlStateSelected];

If you've got a button that's hooked up to an action in your code, you can change the title without an instance variable.

For example, if the button is set to this action:

-(IBAction)startSomething:(id)sender;

You can simply do this in the method:

-(IBAction)startSomething:(id)sender {
    [sender setTitle:@"Hello" forState:UIControlStateNormal];
}

Or if you're wanting to toggle the name of the button, you can create a BOOL named "buttonToggled" (for example), and toggle the name this way:

-(IBAction)toggleButton:(id)sender {
    if (!buttonToggled) {
        [sender setTitle:@"Something" forState:UIControlStateNormal];
        buttonToggled = YES;
    }
    else {
        [sender setTitle:@"Different" forState:UIControlStateNormal];
        buttonToggled = NO;
    }
}

[myButton setTitle:@"Play" forState:UIControlStateNormal];