I have exclusively expressed for my DD from birth, she is now 23 weeks old. She has had 1 formula feed per day since she was 3 months old which was upped to 2 feeds per day at 4 months. I want to move to just formula feeds by the time she is 6 months old. Do I need to stop expressing gradually? Do I need to move to formula gradually or can I just replace all her BM feeds with formula in one go? Any advice appreciated.