You can freeze it.
Also, you can boil it to reduce it as the fat has already been removed from the stock so fat emulsification will not be a problem.
I freeze stock in large containers for a batch of soup, in small containers for an individual portion and in even smaller portions (ice cube trays, or a little larger) for use in sauces and gravies. You can pop the smallest ones into a ziplok and keep them in the freezer in just the bag.
"If you want to make an apple pie from scratch, you must first create the universe." -Carl Sagan