Reheating formula

We use the ready made formula in he 32 oz bottles and store it in the fridge and warm it up throughout the day. I just warmed up a bottle for my daughter but she fell back asleep by time it was ready. I know you can’t reheat formula after a baby has started eating it because of the bacteria in their mouths, but since she never touched the bottle could I re-refrigerate it to reheat in a few hours when she wakes back up? Or since I’ve warmed it once is it done for? I don’t want to waste 6 oz if I don’t have to! Help!