May I know how do you change formula from nan 1 to nan 2 ? I tried to change but lo don't like so I mix the two formula till now I giving him 4 scoop nan1 and 2 scoop nan 2 , how can I totally change to nan 2?

When you transition from one stage to another, alternate the feeds - and not mix two different types of formula together. Start with the feed that LO would least likely be rejecting, eg. a morning feed. Switch that to stage 2 formula for the first few days then slowly replace 2, 3, 4 feeds the same way until every feed is replaced with stage 2! You shouldn't be mixing the formula scoops for one feed, or trying to thicken/dilute formula by adding more/less water. Always prepare formula milk based on the instructions and scoop given in the tin!