Hold it in your oven at 145 -150 ish. If your oven won't go that low, put your wrapped brisket in, turn the oven on it's lowest possible setting and during the preheat, turn it off when it hits about 180 and leave the door closed. Monitor the temp of your brisket and if it gets down to about 145, turn the oven back on and repeat process. You can hold brisket for quite a long time this way.