Sleep train

I gave my daughter lesser milk when she was about 2 months old to train her not to wake up. Every few days reduced by 30ml. After I reduced to 60ml (she was drinking 120ml during the day), she got fed up and never woke up. Took me about 2 weeks plus. My son didnt need any training. He slept through when he turned 1 month. Every child is different. If you are not comfortable reducing the milk quantity, then you have to wait for your child to sleep through on his/her own. Hope this helps!