Maybe I am missing something, but why not drop the 3rd and 4th from your ressie? This frees the room up for someone else, and you can have the dining plan for 5 nights. It also saves you two nights' worth of points.
And, even if you have some reason to keep the first two nights, be careful of losing the entire reservation. I'm not totally sure, but isn't there some policy on canceling a reservation if you don't show up without a call?
I admit, I am exhausted, so maybe I haven't seen some obvious detail.