1y 2 mth lo having diarrhoea. Since change to stage 3. It has been a week Isit ok to change to dumex

Lactose Free Formula Milk A. Lactose-free milk 1. Nestle NAN LACTOGEN Lactose-Free Formula (Stage 1) 2. Similac Total Comfort (Stage 1-3) B. Soy Formula 3. Isomil Soy Formula 850g (Stage 1-3) 4. Dumex Mamil Gold Soy Formula 5. Enfamil A Stage 1 Soy Infant Formula 6. Gerber, Good Start, Soy Based Powder Infant Formula