There is no limit as to where you can slide your vacation, as long as you are senior enough to 'hold' the slide you are asking for. Every year since the Slide was enacted, I have been able to slide my vacations over both Thanksgiving and Christmas/New Years.

As the bids are run, a stack of unwanted trips will develop over those holidays. If you are about half way up regular lines in your category, you should be able to slide over the holidays. I. e. if you could hold the holiday off in a regular bid, you should also be able to slide your vacation over it. Or if you really want some more time off and you are senior enough, you could slide your vacation to a few days before/after the holiday, then bid (and hold) the holiday off too. (and then green slip over the holiday)

But if you are JUNIOR in your category, and you cannot hold it off, or you would have been 'unstacked' into a trip over the holiday, it won't let you slide your vacation over that holiday, as the stack is getting too high at that point and everyone remaining is going to get 'unstacked' into a trip over the holiday.

Bottom line; "It Depends". Mostly on how senior you are in category, and how your category is staffed. Call the Bid Assist guys and they can give you more gouge on vacation slide and trying to avoid working on T-Day or X-Mas.