You don't have much of a choice. The product was intended for restaurant use. If it's defrosted in the fridge and broken down onto serving-sized amounts, it can safely be refrozen. Texture isn't an issue as it's a liquid. Then just defrost, heat and add water to the desired thickness.
Thanks Andy for the info on refreezing liquid food items. I did feel that the whole block was meant as a day's supply for a restaurant. I had visions of her getting out a hack saw and cutting off a piece. And having never refrozen any liquid food item, I didn't go that route.
Illegitimi non carborundum!
I don't want my last words to be, "I wish I had spent more time doing housework"
You can also just make a slurry, which is a thick mixture of water and flour. Whisk it until smooth, then add it to your thin beefy broth, while continuing to whisk it in. Let it simmer on low for 5 or 10 minutes to cook the flour. If it comes up lumpy, just strain your gravy before serving..