There's been an event scheduled on Saturday, November 26th at 9pm ET since the schedule was published in the beginning of the month. We didn't change any times or dates, we simply switched the events that were being held during those times.
The reason for the change is that the "Shiver Me Timbers" event requires at least two EMs to run it, while the Healer's Guild event can be done with one. Dross wasn't sure that he'd be able to assist on Saturday, hence we flip flopped the events should his holiday responsibilities keep him from attending Saturday's event.