Depends what kind of mood they are in,
Apologise, say you understand the implications to your job and stead within the company due to your lateness, say you'll do your very best to prevent it happening again, and offer to work the hours you owe free of charge (yeah, sucks, but your reputation may somewhat be restored if you show dedication at this point).
Apologise, say you understand the implications to your job and stead within the company due to your lateness, say you'll do your very best to prevent it happening again, and offer to work the hours you owe free of charge (yeah, sucks, but your reputation may somewhat be restored if you show dedication at this point).