How to set yourself as "Not Attending" for an instance of a recurring meeting you've Organized?

Meeting organizer is required to attend by default.

If you have an iPhone with iOS 7 or iOS 8, you can try to exploit a bug to make the meeting organizer optional.

Potential Workaround:

If your concern is to keep your calendar free during that time slot, you can set the "Show As" to "Free" on the meeting stub and your calendar will appear free during that time slot.