Is Isomil advance with omega 3 and 6 good for a baby that is allergic to cow's milk?

I bought some isomil advance with omega 3 and 6 and I want to know if I could feed my granddaughter the powdered formula. She had a rash from the milk-based formula.|||Advance is is a very good formula but not good for a baby with milk allergies. You want a formula that is soy based. I would ask the baby's doctor for a recommendation before I gave any formula that the baby could be allergic to. The thing with allergies to food is that each reaction has a tendency to be worse and I wouldn't trust just anyone to tell me what to use.