Slowly increase stage 2 to her feeding. Eg: (5 feed per day) Day 1: 4 feed on stage 1 & 1 feed on stage 2 Day 2: 3 feed on stage 1 & 2 feed on stage 2 Day 3: 2 feed on stage 1 & 3 feed on stage 2 Day 4: 1 feed on stage 1 & 4 feed on stage 2 Day 5: stage 2
What I did was, eg 1 scoop new fm + 2 scoops of current fm. Try it out for 1 day. Next day , 2 scoops new fm + 1 scoop of current fm. Then fully transit to new fm. Only when my lo was 1yo, I did was 1 feed new fm straight away.