@Poonam , the same was instructed to me. How did you do it? To reduce I mean, quantity in the bottle or number of bottles?
I did the number of bottles, so she was on 5 top ups a day to begin with and reduced this down. I guess you could also do quantity but I found I was able to settle her for some feeds and not others. Generally evening top up was a must and was the last to be dropped.
I was instructed the same and slowly reduced the number of tops up per day slowly over a few weeks while my breast milk supply increased to fulfill this need